Problem:
A researcher is interested in whether people's stress levels vary depending on the time of year. The researcher recruits five participants for their study. They ask the participants in mid-July on a scale from 1 to 20. How stressed they felt on average (where a higher score means greater stress) Then, in mid-January, they asked the same five participants again to report how stressed they felt on average. Their average stress levels in July were 1 and in January they were 15.
State whether you decide to reject, or fail to reject, the null hypothesis, and choose the correct explanation for why you made that decision.
A) Reject the null hypothesis; the probability of obtaining this sample mean difference when the null hypothesis is true is less than 5% (p < .05)
B) Reject the null hypothesis; the probability of obtaining this sample mean difference when the null hypothesis is true is greater than 5% (p > .05)
C) Fail to reject the null hypothesis; the probability of obtaining this sample mean difference when the null hypothesis is true is greater than 5% (p > .05)
D) Fail to reject the null hypothesis; the probability of obtaining this sample mean difference when the null hypothesis is true is less than 5% (p < .05)