Understanding Probability and Statistical Notation
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Questions and Answers

Two dice are rolled. What is the probability of rolling a sum of 5?

  • 1/36
  • 1/9 (correct)
  • 1/12
  • 1/6

What is the probability of not rolling a 5 or 6 on a standard six-sided die?

  • 1/6
  • 5/6
  • 1/3
  • 2/3 (correct)

A coin is tossed 5 times, and each time it lands on heads. According to the gambler's fallacy, what is most likely to happen on the next toss?

  • The probability of tossing tails is higher than heads on the next toss.
  • The coin is biased, so heads is still more likely.
  • The probability of tossing heads or tails is still 50/50. (correct)
  • The probability of tossing heads is higher than tails on the next toss.

Which of the of the following best describes Gambler's Fallacy?

<p>Assuming patterns in random events influence future outcomes. (C)</p> Signup and view all the answers

Which cognitive bias leads to an inaccurate judgment due to overvaluing a recent event or information?

<p>Recency Bias (A)</p> Signup and view all the answers

In empirical probability determination, why is it important to analyze probabilities within their specific context?

<p>To understand how ecological, cultural, or other factors may influence outcomes. (A)</p> Signup and view all the answers

In an archaeological survey, 15 test pits are dug in a lowland area and 5 contain artifacts, while 10 test pits are dug in a highland area and 6 contain artifacts. What is the probability of finding archaeological materials in a test pit in the highland area?

<p>0.60 (A)</p> Signup and view all the answers

What does empirical determination of probability involve when compared to calculating probability with known finite spaces?

<p>Estimating probabilities based on observed data. (A)</p> Signup and view all the answers

A researcher is evaluating the effectiveness of a new drug. According to probability theory, what does a p-value of 0.01 (1%) indicate regarding the likelihood of the observed results if the drug has no effect?

<p>There is a 1% chance of observing the results, or more extreme results, if the drug has no effect. (A)</p> Signup and view all the answers

Which of the following statements best describes the Law of Large Numbers?

<p>As the number of trials increases, the proportion of occurrences of a particular outcome gets closer to its true probability. (B)</p> Signup and view all the answers

A standard six-sided die is rolled twice. What finite probability space represents all the possible outcomes of this experiment?

<p>A set of 36 outcomes, representing all possible pairs of numbers that can be rolled. (B)</p> Signup and view all the answers

Events A and B are mutually exclusive. If P(A) = 0.3 and P(B) = 0.4, what is the probability of either A or B occurring?

<p>0.7 (B)</p> Signup and view all the answers

A bag contains 5 red balls and 3 blue balls. What is the probability of randomly drawing a red ball, followed by a blue ball, assuming the first ball is NOT replaced before drawing the second ball?

<p>15/56 (A)</p> Signup and view all the answers

A researcher wants to ensure their findings are highly representative of the population. How should they use the Law of Large Numbers in their study design?

<p>By increasing the number of observations or trials to converge on the true population probability. (D)</p> Signup and view all the answers

A weather forecast states that the probability of rain tomorrow is 30%. Which of the following interpretations is most accurate?

<p>In similar weather conditions, it has rained on 30 out of 100 days. (B)</p> Signup and view all the answers

What is the probability of rolling a 6 on a standard six-sided die, and then flipping a coin and getting heads?

<p>1/12 (B)</p> Signup and view all the answers

When deciding whether to visualize data, what primary consideration should guide the decision?

<p>Whether the visualization will clarify the data or results for the audience. (B)</p> Signup and view all the answers

What is the most important guiding principle when using colors and symbols in a graph?

<p>Using colors and symbols consistently to clarify data, avoiding confusion. (D)</p> Signup and view all the answers

Before creating a graph, what is the FIRST question one should ask?

<p>Should this data or result be visualized? (C)</p> Signup and view all the answers

In addition to the graph itself, what accompanying element is essential for effectively communicating the data's meaning?

<p>Effective figure captions that are referenced in the main text. (C)</p> Signup and view all the answers

What is the primary consideration when choosing the appropriate type of graph for a particular dataset?

<p>The type of variables involved (discrete, continuous, ordered categories) and the intended insights. (D)</p> Signup and view all the answers

When constructing a bar graph, what effect does starting the axis scale at a value significantly higher than zero typically have on the visual representation of the data?

<p>It falsely exaggerates the perceived differences between groups. (C)</p> Signup and view all the answers

What is a primary reason why pie charts are generally discouraged for data visualization?

<p>Humans struggle to accurately differentiate angles. (D)</p> Signup and view all the answers

A study examines the relationship between two continuous variables, and the researcher wants to visually represent this relationship. Which type of graph would be most appropriate?

<p>Scatter plot (B)</p> Signup and view all the answers

In the context of data visualization, what is the main purpose of a box plot?

<p>To visualize and compare distributions of data. (D)</p> Signup and view all the answers

When should a line graph include zero on the Y axis?

<p>Only if the data includes values close to zero. (B)</p> Signup and view all the answers

What critical information should always be included in a figure caption to ensure the graph is properly understood?

<p>Descriptive title and figure number, symbol/color definitions, sample size, explanation of graph parts, and statistical results. (A)</p> Signup and view all the answers

In a histogram displaying class test scores, what does the size of the bins (width of each bar) represent?

<p>The range of scores grouped into each bar. (B)</p> Signup and view all the answers

A researcher is creating a bar graph to compare the average income across three different cities. To avoid misleading interpretations, what is the MOST important guideline they should follow regarding the axis?

<p>Always start the axis at zero to accurately represent the proportions. (B)</p> Signup and view all the answers

If a study finds a relative risk of 0.7 for developing a certain condition in an exposed group compared to a control group, how should this be interpreted?

<p>The exposed group has a 30% lower risk of developing the condition. (C)</p> Signup and view all the answers

In a study comparing smokers to non-smokers regarding the development of lung cancer, what does a relative risk of 2.5 imply?

<p>Smokers are 2.5 times more likely to develop lung cancer than non-smokers. (D)</p> Signup and view all the answers

In a study assessing the impact of a new medication on disease incidence, the absolute risk in the treatment group is 5% and in the control group is 8%. What does this indicate about the medication's effect?

<p>The medication reduces the risk of the disease. (B)</p> Signup and view all the answers

What does a relative risk of 1.0 suggest regarding the difference in risk between two groups?

<p>Little to no difference in risk between the two groups. (D)</p> Signup and view all the answers

If the absolute risk of developing a disease over a 5-year period is 10%, what does this metric primarily describe?

<p>The risk of developing the disease within that specific 5-year timeframe. (D)</p> Signup and view all the answers

Suppose the absolute risk of a certain event is 20% in group A and 10% in group B. Which calculation would determine the relative risk?

<p>20% / 10% = 2 (B)</p> Signup and view all the answers

In comparing the risks between two groups, what key piece of information does relative risk provide that absolute risk does not?

<p>The potential impact of a specific exposure or behavior. (B)</p> Signup and view all the answers

If the relative risk of developing a condition for an exposed group is 1.0, and the absolute risk in the unexposed group is known to be 5%, what is the absolute risk in the exposed group?

<p>5% (A)</p> Signup and view all the answers

In the context of Null Hypothesis Significance Testing (NHST), what is the primary purpose of setting a significance threshold (e.g., p < 0.05)?

<p>To determine the probability of observing the data if the null hypothesis is true, and reject the null hypothesis if this probability is sufficiently low. (C)</p> Signup and view all the answers

A researcher conducts a study and obtains a p-value of 0.03. Assuming a significance level of α = 0.05, what is the correct interpretation of this result?

<p>There is sufficient evidence to reject the null hypothesis. (B)</p> Signup and view all the answers

What is the fundamental question that Null Hypothesis Significance Testing (NHST) aims to address?

<p>Are the patterns observed in our data likely due to chance, or do they reflect a real effect? (B)</p> Signup and view all the answers

In hypothesis testing, what does failing to reject the null hypothesis imply?

<p>There is not enough evidence to support the alternative hypothesis. (B)</p> Signup and view all the answers

A researcher sets their significance level (alpha) to 0.01 instead of the conventional 0.05. What is the consequence of this choice?

<p>It decreases the probability of making a Type I error. (C)</p> Signup and view all the answers

A dataset contains the following values: 5, 7, 7, 9, 11, 13. Which of the following statements is true regarding the mean and median of this dataset?

<p>The mean and median are equal. (D)</p> Signup and view all the answers

In a dataset with several extreme outliers, which measure of central tendency would be the MOST reliable indicator of the 'typical' value?

<p>Median (C)</p> Signup and view all the answers

A researcher is analyzing income data for a city and discovers that the distribution is heavily skewed to the right. Which measure of central tendency would BEST represent the 'center' of the income distribution?

<p>Median (B)</p> Signup and view all the answers

Which of the following is the MOST accurate definition of 'mode'?

<p>The most frequently occurring value in a dataset. (D)</p> Signup and view all the answers

A real estate company wants to determine the 'typical' home price in a neighborhood. They have data on the prices of all homes sold in the last year, but the dataset includes a few multi-million dollar mansions. Which measure of central tendency would provide the MOST representative value for a typical home in this scenario?

<p>Median (C)</p> Signup and view all the answers

What is a key characteristic of an asymmetrical distribution?

<p>Half of the values are above, and half are below, the median. (C)</p> Signup and view all the answers

Why is the mode typically less useful for continuous data compared to discrete data?

<p>Continuous data lacks distinct, frequently repeated values. (B)</p> Signup and view all the answers

Which measure of dispersion is most sensitive to extreme values in a dataset?

<p>Range (D)</p> Signup and view all the answers

What does the interquartile range (IQR) primarily describe?

<p>The variation within the middle 50% of the data. (C)</p> Signup and view all the answers

What is the primary reason for squaring the deviations from the mean when calculating variance?

<p>To prevent positive and negative deviations from canceling each other out. (A)</p> Signup and view all the answers

If the variance of a dataset is 25, what is the standard deviation?

<p>5 (A)</p> Signup and view all the answers

Why is the standard deviation a more intuitive measure of dispersion than variance?

<p>Standard deviation is expressed in the same units as the original data. (C)</p> Signup and view all the answers

Under what circumstances is the coefficient of variation (CV) most useful?

<p>When comparing the dispersion of datasets with different units or scales. (A)</p> Signup and view all the answers

Which of the following measures is least affected by outliers in a dataset?

<p>Interquartile Range (C)</p> Signup and view all the answers

A researcher finds that the standard deviation of plant heights in a sample is 5 cm. However, the researcher wants to compare this variability to another sample where the average height is significantly different. What would be the most appropriate measure to use?

<p>Coefficient of Variation (D)</p> Signup and view all the answers

In statistical analysis, how does the term 'significant' differ from its everyday usage?

<p>Statistical significance indicates a result is unlikely to have occurred by chance, while everyday usage implies importance or consequence. (D)</p> Signup and view all the answers

Which statistical measure is most commonly used to determine statistical significance?

<p>P-value (C)</p> Signup and view all the answers

A researcher obtains a statistically significant result (p < 0.05) in a study. What is the most accurate interpretation of this finding?

<p>There is strong evidence against the null hypothesis; the observed results are unlikely due to chance. (B)</p> Signup and view all the answers

What is a key limitation of relying solely on statistical significance (p-value) in research?

<p>It does not provide information about the size or importance of the observed effect. (B)</p> Signup and view all the answers

In the context of statistical hypothesis testing, what does a higher p-value (e.g., p = 0.40) suggest?

<p>Strong evidence in favor of the null hypothesis. (D)</p> Signup and view all the answers

When using graphs for data analysis, which of the following is a primary purpose during the analysis phase?

<p>To examine relationships between variables and identify patterns. (D)</p> Signup and view all the answers

A researcher notices extreme values in their dataset. What should be their initial consideration regarding these outliers?

<p>Determine if these values are due to normal sample variation or represent 'bad' data caused by errors. (D)</p> Signup and view all the answers

In which scenario is a bar graph most appropriate?

<p>Comparing counts or frequencies across different categories. (D)</p> Signup and view all the answers

When should a line graph be used?

<p>When illustrating relationships between ordered categories or changes over time. (D)</p> Signup and view all the answers

A researcher wants to illustrate how the mean and variability of a continuous variable change over time. Which type of graph would be most suitable?

<p>Means plot (line graph with error bars) (B)</p> Signup and view all the answers

For what purpose is a box plot most effectively used?

<p>To compare the distributions of continuous data across different samples. (C)</p> Signup and view all the answers

A researcher suspects that their continuous dataset contains subgroups. Which type of graph is most suitable for visually identifying such subgroups?

<p>Histogram (D)</p> Signup and view all the answers

A company wants to present its quarterly profits over the last 5 years. The goal is to highlight both the average profit for each quarter and the range of profit values observed. Which graph would be most effective?

<p>A means plot showing the mean quarterly profit with error bars representing the variability. (D)</p> Signup and view all the answers

A researcher is studying the average height of students at a university. They collect multiple random samples and calculate the mean height for each sample. What does the distribution of these sample means represent?

<p>The sampling distribution of the sample means. (D)</p> Signup and view all the answers

In what way does increasing the sample size affect the properties of the sampling distribution of means?

<p>It decreases the spread (variability) of the sampling distribution. (C)</p> Signup and view all the answers

A researcher wants to estimate a population parameter with a high level of confidence. How does the choice of confidence level affect the width of the confidence interval derived from the sampling distribution?

<p>A higher confidence level results in a wider confidence interval. (A)</p> Signup and view all the answers

Why is it important to examine the shape of a sample distribution when making inferences about a population?

<p>The shape of the sample distribution provides insights into the underlying population distribution and the appropriateness of certain statistical tests which assume a particular distribution shape. (A)</p> Signup and view all the answers

What is the central limit theorem's (CLT) significance when analyzing sample distributions?

<p>The CLT states that, under certain conditions, the sampling distribution of the sample mean will approximate a normal distribution, regardless of the shape of the population distribution. (D)</p> Signup and view all the answers

Why is visual inspection (histograms, density plots, Q-Q plots) considered important when assessing the normality of a sample?

<p>Visual inspection provides an intuitive understanding of the distribution's shape and potential deviations from normality, which complements statistical tests. (D)</p> Signup and view all the answers

Even though perfectly normal samples are rare in real-life data, why is assessing normality still a crucial step in statistical analysis?

<p>Because parametric statistical tests assume normality. (A)</p> Signup and view all the answers

In the context of Q-Q plots, what does it indicate when the data points deviate noticeably from the straight line?

<p>The data deviates from a normal distribution. (A)</p> Signup and view all the answers

How should a researcher address a non-normal sample?

<p>Apply a transformation to the data. (A)</p> Signup and view all the answers

What characteristic of a distribution does kurtosis primarily describe?

<p>The peakedness and tail weight relative to a normal distribution. (D)</p> Signup and view all the answers

In an asymmetrical distribution, which of the following statements is generally true regarding the mean, median, and mode?

<p>They all have different values. (A)</p> Signup and view all the answers

When can sample statistics from an asymmetrical and kurtotic distribution be considered reliable estimators of population parameters?

<p>It depends on the specific parameters being estimated and the degree of asymmetry/kurtosis. (C)</p> Signup and view all the answers

Why are theoretical distributions useful in inferential statistics?

<p>They provide a baseline to compare observed sample distributions against, allowing for inferences about the population. (D)</p> Signup and view all the answers

Which characteristic is NOT a property of a normal distribution?

<p>Skewed to the right (B)</p> Signup and view all the answers

What does the area under a curve in probability distribution directly represent?

<p>The probability of a value falling within that range (B)</p> Signup and view all the answers

In a normal distribution, if two distributions, A & C, have little area of curve overlap, what is implied about drawing a value from both distributions?

<p>There is a low probability of drawing the same value from both distributions. (D)</p> Signup and view all the answers

What is the primary purpose of calculating Z-scores?

<p>To standardize sample variates by expressing them in terms of standard deviations from the mean (D)</p> Signup and view all the answers

In statistical terms, what do location and dispersion statistics primarily define about a normal distribution?

<p>Its central tendency and spread (D)</p> Signup and view all the answers

In R programming, what is the primary distinction between an atomic vector and a matrix?

<p>An atomic vector can only contain one data type, while a matrix is a 2 dimensional array with homogenous data types (the same type as the vector). (B)</p> Signup and view all the answers

You are writing an R script and want to add explanatory notes within the code. What is the MOST effective way to incorporate these annotations?

<p>Insert comments directly into the R script using a specific notation. (C)</p> Signup and view all the answers

Which of the following statements accurately describes the relationship between R and RStudio?

<p>R is a programming language and environment, while RStudio is an IDE that simplifies working with R. (D)</p> Signup and view all the answers

Consider the following R code: > seq(from = 1, to = 10, by = 1). What does the > symbol typically indicate in this context?

<p>It indicates the start of a line in the RStudio console, not part of the code itself. (C)</p> Signup and view all the answers

In R, you need to store a dataset containing customer information, including names (character), ages (numeric), and whether they are subscribed to a service (logical). Which data structure is most appropriate?

<p>Data Frame (C)</p> Signup and view all the answers

Which scenario exemplifies the use of descriptive statistics?

<p>Calculating the mean test score of students in a class. (A)</p> Signup and view all the answers

What is the primary purpose of inferential statistics?

<p>To make predictions or generalizations about a population based on data from a sample. (C)</p> Signup and view all the answers

A researcher aims to study the political opinions of all adults in Canada. Due to the impracticality of surveying every adult, they collect data from a smaller group. What is this smaller group called in statistical terms?

<p>A sample (B)</p> Signup and view all the answers

In statistical analysis, what term refers to the entire group of individuals, objects, or events that are of interest in a study?

<p>Population (D)</p> Signup and view all the answers

A researcher is studying the average height of trees in a forest. They only measure trees along easily accessible paths, assuming these are representative of the entire forest. What type of issue is most likely to arise?

<p>Bias (A)</p> Signup and view all the answers

If every member of a population does NOT have an equal chance of being selected for a study, what is the likely result?

<p>Bias in the sample (B)</p> Signup and view all the answers

Which scenario best illustrates the potential misuse of statistics?

<p>A news outlet presents data without proper context, leading to a misleading interpretation of crime rates. (C)</p> Signup and view all the answers

What is a crucial limitation to keep in mind when using statistical tools for data analysis?

<p>The validity of the results depends on the quality of the data used. (B)</p> Signup and view all the answers

A researcher is studying the effect of exercise on heart rate. They measure participants' heart rates before and after a workout. Which of the following BEST describes 'heart rate' in this study?

<p>A variable, representing the quantity being measured that can change. (D)</p> Signup and view all the answers

Which of the following scenarios BEST exemplifies the use of ordinal data?

<p>Categorizing customer satisfaction as 'very dissatisfied', 'dissatisfied', 'neutral', 'satisfied', or 'very satisfied'. (D)</p> Signup and view all the answers

A scientist is collecting data on the mass of different rock samples. Which scale of measurement is MOST appropriate for recording this data?

<p>Ratio, since mass is measured on a continuous scale with a true zero point. (B)</p> Signup and view all the answers

A researcher is investigating the effectiveness of a new fertilizer on plant growth. They carefully control the experimental conditions, use precise measurement tools, and define clear criteria for assessing plant health. What aspect of data quality is the researcher primarily addressing through these actions?

<p>All of the above. (D)</p> Signup and view all the answers

Which of the following data types would permit the broadest range of mathematical analyses, including calculations of ratios and meaningful comparisons of absolute differences?

<p>Ratio data, suc h as measuring the height of plants in centimeters. (C)</p> Signup and view all the answers

Flashcards

Probability

The likelihood of an event occurring in a random experiment.

Probability Value (P)

A value between 0 and 1 indicating the likelihood of an event.

Law of Large Numbers

As you repeat an experiment, the observed probability gets closer to the true probability.

Finite Probability Space

All possible outcomes of an experiment.

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Independent and Mutually Exclusive Events

Events that don't affect each other and can't happen at the same time.

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Probability of Mutually Exclusive Events

Add the individual probabilities of each event.

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Probability of 'NOT' an Event

Subtract the probability of the event from 1.

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How to calculate the probability of NOT rolling a 1?

Subtracting a given probability from 1.

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P(Not)

The probability of an event NOT occurring.

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Probability of A and B

Probability of two independent events both happening. This is calculated by multiplying their individual probabilities.

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Independent Events

Events where the outcome of one does not affect the outcome of the other.

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Gambler's Fallacy

The mistaken belief that past events influence independent future outcomes.

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Recency Bias

Overweighing recent events, which affects your judgment.

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Empirically Estimated Probability

Estimating probability through observation when you don't know possible outcomes beforehand.

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Context-Dependent Probabilities

Probabilities that change depending on the environment.

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Goal of a Good Graph

To present data in a way that is clear and easily understood.

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Should Data Be Visualized?

Consider if visualizing the data adds value and insight.

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How Many Graphs is Too Many?

Too many graphs can overwhelm and confuse the audience.

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Effective Figure Captions

Use captions to explain figures and refer to them in the text to guide the reader.

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Effective Use of Colors and Symbols

Use colors and symbols to enhance understanding, but avoid unnecessary complexity.

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Box Plot

Visualizes the distribution of data through quartiles, highlighting the median, range, and outliers.

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Scatter Plot

A graph used to show the relationship between two continuous data variables.

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Line Graph

Used to display changes or trends over different categories or groups.

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Histogram

A visual representation of the distribution of continuous data, showing the frequency of values within specific ranges or bins.

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Bar Graph Axis Scaling

A graph displaying categorical data with rectangular bars. Proper axis scaling is crucial, always starting from zero to avoid misrepresentation.

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Good Figure Captioning

A complete figure caption that provides all the information needed to understand the visualized data, including a descriptive title, symbol definitions, sample size, explanation of the graph parts, and statistical results.

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Pie Chart Weakness

We have trouble perceiving the small differences in angles, shapes, and area of the slices.

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Line Graph Axis

Use axis scales that appropriately accommodate data without excessive blank space to avoid diminishing patterns.

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Absolute Risk

The risk of an event happening over a specific duration.

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Relative Risk

Comparing the risk between two different groups.

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Relative Risk Use

Indicates how much risk can change through a behavioral change.

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Absolute Risk Calculation

Number of people with the disease in the exposed group divided by the total number of people in that group.

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Relative Risk Calculation

Risk in exposed group divided by risk in unexposed group.

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Relative Risk ~1

Little to no difference in risk between groups.

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Relative Risk > 1

Increased risk in the exposed group.

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Relative Risk < 1

Reduced risk in the exposed group.

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Null-Hypothesis Significance Testing

A statistical method used to determine if the patterns observed in sample data are likely due to a real effect or simply random chance.

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Goal of NHST

To assess whether observed patterns (differences or relationships) in a sample are representative of true patterns in the larger population.

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Thresholds of Acceptance in NHST

These approaches often involve comparing a calculated statistic (e.g., p-value) to a predetermined threshold to decide whether to accept or reject the null hypothesis.

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P-Value

The probability of obtaining test results at least as extreme as the results actually observed during the test, assuming that the null hypothesis is correct.

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Interesting Patterns or Random Chance?

An approach to determine whether the patterns observed in data are interesting or simply random chance.

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Examining Samples

Numerical examination of data to identify outliers and make comparisons.

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Sample Statistics

Values that describe characteristics of a sample, estimating population measures.

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Frequency Distribution

Arrangement displaying the number of times each value appears in a dataset.

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Central Tendency

Mean: Average value. Median: Middle value. Mode: Most frequent value.

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N

Sample size (count of observations).

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Asymmetrical Distribution

A distribution where values are not equally distributed around the mean. Half the values are not above or below the median.

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Mode (Mo)

The most frequently occurring value in a dataset.

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Range

A range of values spanning from the smallest to the largest in a dataset or a part of it.

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Interquartile Range

The range between the first quartile (25th percentile) and the third quartile (75th percentile), representing the middle 50% of the data.

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Quartile

Divides data into four equal parts, marked by Q1 (25%), Q2 (50%, median), and Q3 (75%).

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Variance (s²)

A measure of how spread out or clumped together the data points are around the mean.

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Standard Deviation (s, SD)

The square root of the variance, providing a measure of data dispersion in the original units of measurement.

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Coefficient of Variation (CV)

The standard deviation adjusted as a proportion of the mean, allowing comparison of variability between datasets with different scales.

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Sample Variance

The average of the squared differences from the Mean.

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Mode for Discrete Data

A measure of central tendency that identifies the most frequently occurring value in a dataset, particularly useful for discrete data where mean and median might be meaningless.

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Statistical Significance

A statistical result unlikely to occur by random chance alone.

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Significance in Statistics

It is not the same as importance in everyday life.

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Statistical Significance Testing

Uses Null Hypothesis Significance Testing to determine if observed patterns in sample data are likely due to a real effect or merely random chance

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Goal of Statistical Significance Testing

To assess if an observed pattern in a sample represents a true pattern in the larger population.

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Graphs (Plots, Charts)

Visual representations of data, such as plots or charts.

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Why use graphs before analysis?

To examine data shape, identify outliers, and find patterns before in-depth analysis.

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Spotting Outliers

Values distant from the majority of data points

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Bar Graph

Data grouped into distinct categories.

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Categorical Data Comparison

Comparing categories by counts or frequencies

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Means Plot

Shows the change in the mean or variability over time.

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Distribution Shape - Why?

Understanding the shape helps with drawing conclusions from samples.

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Asymmetrical & Kurtotic Distributions

Distributions that do not align with theoretical expectations.

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Theoretical Distribution

A mathematical model describing variable value probabilities.

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Inferential Statistics

Comparing sample data to a standard distribution.

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Normal Distribution Properties

Symmetrical, peak at the mean, asymptotic tails, area = 1.

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Normal Distribution Name

Also known as the Gaussian distribution.

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Area Under the Curve

Represents the percentage of observations within a specific range.

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Z-Score

How many standard deviations a value is from the mean.

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Standardized Sample

Standardizing a sample into units of standard deviation.

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Q-Q Plot

A visual tool to compare the quantiles of your sample data to the quantiles of a theoretical normal distribution.

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Skewed Distributions

Distributions where one 'tail' is longer than the other, indicating an imbalance in the data.

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Fat-tailed Distribution

Distributions with too much data concentrated in the tails compared to a normal distribution.

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Parametric Tests

Tests that assume the data follows a specific distribution (often normal).

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What is R?

A programming language and environment used for statistical computing and graphics.

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What is RStudio?

An Integrated Development Environment (IDE) that simplifies working with the R language by providing tools for coding, debugging, and project management.

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What is a Function in R?

Commands that tell R to perform specific actions, often requiring arguments as inputs.

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What are Arguments in R?

Options or details that provide instructions to a function, specifying how it should operate.

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What is an Object in R?

A way R stores data; can be assigned different data types.

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Statistics

A branch of mathematics focused on the collection, analysis, interpretation, and presentation of numerical data.

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Descriptive Statistics

Examining and summarizing data within a sample.

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Statistical Population

The entire group of items or subjects of interest in a study.

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Sample

A representative subset of a population, used to gather data and make inferences about the population.

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Bias

Systematic error that occurs if every member of the population does not have an equal chance of being selected into the sample.

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Descriptive Role

Using statistical tools to describe and summarize data.

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Inferential Role

Using statistical tools to make predictions or generalizations about a population based on sample data.

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Data

The complete set of observations.

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Datum/Data Point

A single observation or measurement within a dataset.

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Variable

A measurable quantity that can take on different values.

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Discrete Data

Data grouped into categories based on a specific trait and counted, using only whole numbers.

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Ordinal Data

Data with ordered categories where the intervals are not equal.

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Study Notes

  • 5% of the time, we will incorrectly conclude populations differ (or variables are associated), when they actually do not
  • Reduce A, reduce likelihood of Type I error.
  • Type II error: Is defined as failing reject HO when it is actually fals
  • thus fail to detect a true difference
  • in this case, a true difference between data populations fails to be measured, as a relationship has failed to be displayed by the samples
  • Note: in type II data, not much can inferred, we can only infer from available data to hand

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Description

Explore probability's role in statistics, indicating the likelihood of sample patterns reflecting population reality. Learn about outcome probability, statistical notation, and the Law of Large Numbers. Understand how researchers determine event likelihood and manage uncertainty.

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