A Professor Finds That the Average SAT Score Among All $\mu$

Multiple Choice

A professor finds that the average SAT score among all students attending his college is 1150 ± 150 ( $\mu$ ± $\sigma$ ) .He polls his class of 25 students and finds that the average SAT score is 1200.Suppose he computes a one-sample z test at a .05 level of significance.What is his decision?

A) to reject the null hypothesis
B) to retain the null hypothesis
C) to reject the null hypothesis for a two-tailed test, but to retain the null hypothesis for an upper-tailed test
D) to reject the null hypothesis for an upper-tailed test, but to retain the null hypothesis for a two-tailed test