Introduction to Statistics
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Questions and Answers

What is the key difference between a quantitative and qualitative variable?

  • Quantitative variables are always measured in whole units, while qualitative variables use fractional units.
  • Quantitative variables vary by amount and are measured numerically, and qualitative variables vary by class and are typically non-numeric. (correct)
  • Qualitative variables can be measured in fractional units, but quantitative variables cannot.
  • Qualitative variables are numerical and vary by amount, while quantitative variables vary by class and are non-numeric.

    • Which of the following describes a measure of central tendency?

  • A statistical measure that calculates the total number of scores in a distribution.
  • A single score that measures the spread of scores in a distribution.
  • A single value that is most descriptive of all scores in a distribution. (correct)
  • The variability of the sample in comparison to the variability of the population.

    • What effect does an outlier typically have on the mean of a data set?

  • The mean shifts toward the value of the outlier. (correct)
  • The mean is directly proportional to the value of the outlier.
  • The mean shifts away from the value of the outlier.
  • The mean is unaffected by an outlier.

    • Which of the following is NOT considered a measure of central tendency?

    <p>Sample size</p> Signup and view all the answers

    Which type of variable is most likely to be measured using fractional units?

    <p>A quantitative variable</p> Signup and view all the answers

    A researcher is interested in the average income of households in a city. If they calculate the average income from a sample and use this information to predict the average income of all households in the city, which type of statistics are they using?

    <p>Inferential statistics</p> Signup and view all the answers

    If a researcher measures the height of individuals and then calculates the average height, what type of statistic is that?

    <p>Descriptive statistic</p> Signup and view all the answers

    Which of the following best describes a 'population parameter'?

    <p>A characteristic that describes a population.</p> Signup and view all the answers

    What is the primary goal of using inferential statistics?

    <p>To make generalizations about a population based on a sample.</p> Signup and view all the answers

    Which of these options constitutes a 'datum'?

    <p>The age of an individual person.</p> Signup and view all the answers

    A researcher is looking at the impact of a new drug on patients. They take a sample of patients and measure the impact of the drug. What is the sample statistic in this situation?

    <p>The average impact of the drug only on those who were chosen to be tested.</p> Signup and view all the answers

    The statement 'There are lies, damned lies, and statistics' suggests that:

    <p>Statistics can be used to mislead or misinterpret data.</p> Signup and view all the answers

    What is the primary purpose of the 'research method'?

    <p>To establish systematic techniques for acquiring and modifying knowledge.</p> Signup and view all the answers

    Which of the following scales of measurement does NOT possess a true zero point?

    <p>Interval</p> Signup and view all the answers

    Which scale of measurement is characterized by meaningful order, equal intervals between values, and a true zero point?

    <p>Ratio</p> Signup and view all the answers

    If the numbers assigned to a variable are simply labels and have no meaningful numerical order, what type of measurement scale is being used?

    <p>Nominal</p> Signup and view all the answers

    A researcher ranks participants based on their performance in a competition. Which measurement scale is being used in this case?

    <p>Ordinal</p> Signup and view all the answers

    What is a common practical reason for coding nominal data with numeric values in research?

    <p>It makes the data easier to enter and analyze in statistical software.</p> Signup and view all the answers

    Which of these represents a variable that is typically measured on a ratio scale?

    <p>Weight in kilograms</p> Signup and view all the answers

    In what way is an interval scale different from an ordinal scale?

    <p>Interval scales have meaningful order and equal intervals</p> Signup and view all the answers

    Which statement best describes the relationship between qualitative and quantitative variables?

    <p>Quantitative variables are fundamentally different from qualitative variables.</p> Signup and view all the answers

    Given the scales of measurement discussed, which of the following presents the correct hierarchy from least to most informative?

    <p>Nominal → Ordinal → Interval → Ratio</p> Signup and view all the answers

    What is a key characteristic that distinguishes a continuous variable from other types of variables?

    <p>It can be measured at any point beyond the decimal.</p> Signup and view all the answers

    Which statement correctly describes the effect of outliers on the mean and median in a data set?

    <p>Outliers affect the mean but not the median.</p> Signup and view all the answers

    If a new score is added that is less than the current mean, what will happen to the mean?

    <p>The mean will decrease.</p> Signup and view all the answers

    What is the formula for calculating the weighted mean?

    <p>Mw = Σ(x * n) / Σn</p> Signup and view all the answers

    What happens to the mean when a score equal to the mean is removed from a data set?

    <p>The mean remains unchanged.</p> Signup and view all the answers

    When calculating the sum of the differences of each score from the mean, what should the total equal?

    <p>The total equals zero.</p> Signup and view all the answers

    If all scores in a distribution are multiplied by a constant, how will the mean be affected?

    <p>The mean will change by that constant.</p> Signup and view all the answers

    In terms of measurement levels, the median can be used for which types?

    <p>Ordinal, interval, and ratio levels of measurement.</p> Signup and view all the answers

    Which scenario would not change the value of the mean?

    <p>Adding a new score equal to the mean.</p> Signup and view all the answers

    Study Notes

    Introduction to Statistics

    • Statistics is the study of how data can be described and inferences can be made from data
    • Descriptive statistics organize, summarize, and make sense of data (usually graphically, in tables, or as summary statistics)
    • Inferential statistics interpret data to answer questions or make decisions
    • Data are measurements or observations that are typically numeric

    Descriptive Statistics

    • Used to quantify behavior
    • Summarize individual scores into more meaningful values (mean, median, mode)

    Inferential Statistics

    • Reach conclusions based on evidence and reasoning
    • Infer from samples to larger populations
    • Population parameter = characteristic of a population
    • Sample statistic = characteristic of a sample

    Research Methods and Statistics

    • Science studies phenomena using strict observation, evaluation, interpretation, and theoretical explanation
    • Scientific method = set of systematic techniques for acquiring and integrating knowledge about observable phenomena

    Scales of Measurement

    • Scales of measurement define how numerical properties change with different uses
    • Different scales imply different amounts of information

    Nominal Scale

    • Numbers are assigned to represent something or someone (e.g., sex, race, hair color).
    • No meaningful ranking possible. Coding is arbitrary.

    Ordinal Scale

    • Measurements express order or rank.
    • Indicates one value is greater or less than another.
    • Differences between ranks are unknown.

    Interval Scale

    • Measurements with no true zero.
    • Units are equidistant (equal).
    • E.g., temperatures in Celsius degrees

    Ratio Scale

    • Measurements with a true zero.
    • Units are equidistant.
    • Provides most amount of information.
    • E.g., counts, measures of length, height, weight, time

    Quantitative Variables

    • Describe amounts
    • Can be continuous or discrete
    • Continuous = measured along a continuum (e.g., temperature)
    • Discrete = measured in whole units or categories (e.g., number of errors)
    • Quantitative variables can be further classified as discrete or continuous

    Qualitative Variables

    • Label categories or characteristics
    • Can only be discrete
    • E.g., sex, marital status, color, size

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    Related Documents

    Chapter 1 - Introduction to Statistics PDF

    Description

    Explore the fundamental concepts of statistics, including descriptive and inferential techniques. Learn how to organize, summarize, and interpret data through various methods. This quiz covers key terms and applications relevant to statistics.

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