Podcast
Questions and Answers
What effect does increasing the sample size have on the width of a confidence interval?
What effect does increasing the sample size have on the width of a confidence interval?
- It decreases the width of the confidence interval. (correct)
- It can either increase or decrease the width depending on the standard error.
- It increases the width of the confidence interval.
- It has no effect on the width of the confidence interval.
In hypothesis testing, what is a correct definition of a p-value?
In hypothesis testing, what is a correct definition of a p-value?
- The probability of making a type-1 error.
- The probability of observing data as extreme as observed, given that the null hypothesis is true. (correct)
- The probability of the null hypothesis being true.
- The threshold at which the null hypothesis is rejected.
What would correctly constitute a null hypothesis when testing for the difference in means between two groups?
What would correctly constitute a null hypothesis when testing for the difference in means between two groups?
- At least one group has a significantly different mean.
- The means of the two groups are equal. (correct)
- The means of the two groups are not equal.
- The means of both groups are assumed to be greater than a specific value.
When using a bootstrap distribution to construct confidence intervals, what calculation is commonly applied?
When using a bootstrap distribution to construct confidence intervals, what calculation is commonly applied?
In the context of hypothesis testing, what is a type-2 error?
In the context of hypothesis testing, what is a type-2 error?
What is the main difference between a population and a sample?
What is the main difference between a population and a sample?
Which variable in a regression analysis describes the variable that is being predicted?
Which variable in a regression analysis describes the variable that is being predicted?
In hypothesis testing for two categorical variables, which of the following steps is NOT required?
In hypothesis testing for two categorical variables, which of the following steps is NOT required?
What does the R-squared value in regression analysis represent?
What does the R-squared value in regression analysis represent?
What type of variable is a confounding variable?
What type of variable is a confounding variable?
Which of the following describes the concept of standard error?
Which of the following describes the concept of standard error?
In the context of linear regression, what does the slope indicate?
In the context of linear regression, what does the slope indicate?
What type of relationship does correlation measure between two variables?
What type of relationship does correlation measure between two variables?
Flashcards
Quantitative Variables
Quantitative Variables
Variables that can be counted or measured, like height, age, or temperature.
Categorical Variables
Categorical Variables
Variables that categorize or group data, like hair color, gender, or favorite pet.
Measures of Center
Measures of Center
A measure that describes the center of a dataset, like the average or median.
Measures of Spread
Measures of Spread
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Univariate Graphical Displays
Univariate Graphical Displays
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Bivariate Graphical Displays
Bivariate Graphical Displays
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Simple Linear Regression
Simple Linear Regression
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Correlation Coefficient
Correlation Coefficient
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Confidence Interval
Confidence Interval
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Null vs. Alternative Hypothesis
Null vs. Alternative Hypothesis
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P-value
P-value
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Type 1 Error
Type 1 Error
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Type 2 Error
Type 2 Error
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Study Notes
STAT 200 Learning Objectives
- Variables: Explain, recognize, and provide examples of categorical and quantitative variables.
- Numerical Summaries: Interpret numerical summaries of center/location (e.g., five-number summaries) and spread (e.g., empirical rule); predict how data changes affect these summaries.
- Graphical Displays: Derive information from univariate and bivariate graphical displays (bar graphs, dot-plots, boxplots, histograms, scatterplots).
- Probabilities and Z-scores: Convert values to percentiles or z-scores for normal distributions using technology.
- Linear Regression: Identify and interpret slope, intercept, R-squared values from simple linear regression output; calculate predicted values and residuals. Interpret T-statistic and p-value for the test of slope coefficients.
- Correlation and Bivariate Plots: Match bivariate plots and descriptions to correlation coefficients; calculate correlation from R-squared and slope.
- Descriptive Statistics: Produce and interpret descriptive statistics for tabular data (conditional probabilities, risk, relative risk, odds). Include hypothesis tests for two categorical variables.
- Hypothesis Tests: Perform steps in a hypothesis test of association of two categorical variables from contingency table data; formulate hypotheses, calculate expected counts, find the chi-square statistic, calculate p-value, and interpret results.
- Population vs. Sample: Recognize the difference between population and sample, and between parameter and statistic.
- Sample Size and Standard Error: For large populations, understand that precision of estimation is a function of sample size. Recognize the inverse square root relationship between sample size and standard error.
- Study Types: Recognize randomized experiment vs. observational study and explain implications for causation; define simple random sampling.
- Variables in Studies: Explain, recognize, and cite examples of explanatory, response, and confounding (lurking) variables.
- Confidence Intervals: Recognize the similarity among confidence intervals; exploit this similarity to derive intervals for common population quantities (proportions and means).
- Confidence Interval Details: Give correct informal and formal explanations of confidence intervals; explain how factors like sample size, confidence level, and standard error affect the interval's width.
- Hypothesis Formulation: Correctly construct null and alternative hypotheses about population quantities in real-life situations.
- Test Statistics and P-values: Recognize similarity among test statistics of the standardized score variety (e.g., proportions, means); calculate p-values, define p-value correctly, and interpret p-values and confidence intervals for decision-making.
- Inference Situations: Recognize and distinguish among common inference situations (one mean/proportion, difference of two means/proportions, paired means), apply and interpret confidence intervals and tests in these situations.
- Bootstrap Distributions: Explain how to generate and use a bootstrap distribution to create confidence intervals for means, differences in means, proportions, and differences in proportions; use both formula (statistic ± 2xSE) and percentiles.
- Randomization Distributions: Describe the process of creating a randomization distribution for a given sample and null hypothesis; use technology to calculate p-value, connecting it to the motivation behind a randomization distribution.
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