Question

which of the following best describes a p - value?
a. the probability of observing the data, or something more extreme, if the null hypothesis were true.
b. the likelihood that the alternative hypothesis is false.
c. the probability that the null hypothesis is true.
d. a measure that directly calculates the effect size of the study.

Explanation:

The p - value is a key concept in hypothesis testing. It is not related to the likelihood of the alternative hypothesis being false (option b) as it is centered around the null hypothesis. It is also not the probability that the null hypothesis is true (option c) because hypothesis testing does not give the probability of the null hypothesis being true in an absolute sense. And it is not a measure of effect size (option d). The p - value is specifically defined as the probability of observing the data, or something more extreme, if the null hypothesis were true (option a).

Answer:

a. The probability of observing the data, or something more extreme, if the null hypothesis were true.