申論題

2.(10%) According to the Census Bureau, the mean monthly salary of people with a professional degree was $4,961 in 2020. Assume that this result holds true for the 2020 population of all people with a professional degrec. A random sample of 400 people with a professional degree taken recently showed that their mean monthly salary is $5,067 with a standard deviation of $985.

(1) Find the p-value for the test of hypothesis with the alternative hypothesis that the current mean monthly salary of all people with a professional degree is greater than $4,961. (8%)