Question

when reading a statistical report, the sample size is ___.
a a subset of the population
b has little bearing on the findings
c always > 30
d equal to the population

Explanation:

• Option A: A sample is indeed a subset of the population. For example, if we want to study the heights of all adults (population), we might measure the heights of 500 adults (sample), and the size of this sample (500) is related to this subset.
• Option B: Sample size has a significant bearing on findings. Larger sample sizes generally lead to more reliable and accurate results (e.g., smaller margin of error in estimates), so this option is incorrect.
• Option C: Sample size is not always greater than 30. In some cases (e.g., when studying a rare population or in pilot studies), sample sizes can be smaller. The “sample size > 30” is a rule - of - thumb for some statistical tests (like the Central Limit Theorem approximation for non - normal populations), but it's not an absolute requirement for a sample, so this option is wrong.
• Option D: If the sample size were equal to the population, it would no longer be a sample but a census. Since a sample is by definition a part of the population, this option is incorrect.

Answer:

A. a subset of the population