Can someone please help me understand how to calculate this?

A report in The New York Times (August 7, 2010) suggests that consumers are spending less due to a realization that excessive spending does not make them happier. A reserarcher wants to use debit card data to contradict the generally held view that the average amount spent anuually on a debit card is at least $8,000. She surveys 20 consumers and asks them how much they spend annually on thier debit cards. The resuls are in the le Debit. Use the data to conduct a hypothesis test to determine if the true mean amount spent annually on a debit card is less than $8000. Use alpha = .05. AA. p-value = .0488 alpha = .05. Cannot reject the null hypothesis, there is not enough evidence to conclude that the true mean amount spent annually on a debit card is less than $8000. A C. p-value = .9512 > alpha = .05. Cannot reject the null hypothesis, there is not enough evidence to conclude that the true mean amount spent annually on a debit card is less than $8000. A D. p-value = .0975 > alpha = .05. Cannot reject the null hypothesis, there is not enough evidence to conclude that the true mean amount spent annually on a debit card is less than $8000. \f