Distinguish descriptive and inferential statistics.

• A. Descriptive statistics test hypotheses; inferential statistics summarize data.
• B. Descriptive statistics summarize data with measures of central tendency and dispersion; inferential statistics determine if observed outcomes are due to random variation.
• C. Descriptive statistics estimate population parameters; inferential statistics describe sample data.
• D. Descriptive statistics measure effect size; inferential statistics measure reliability.

Answer: (B)

Distinguishing descriptive from inferential statistics rests on scope and purpose. Descriptive statistics describe what the data show in the sample by summarizing it with measures of central tendency (like the mean, median, and mode) and dispersion (such as the range, variance, and standard deviation). They organize and present the observed data without making claims beyond what was collected.

Inferential statistics, on the other hand, use the sample to make inferences about a larger population. They involve determining whether the observed outcomes could be due to random variation, which underpins hypothesis tests and the estimation of population parameters. This is where confidence intervals and p-values come in, allowing you to generalize beyond the sample.

So the best choice reflects that descriptive statistics summarize data with central tendency and dispersion, while inferential statistics assess whether what’s observed is likely due to chance or reflects true effects in the population.