The Problem Solving Inventory (PSI) has a normal distribution with mean = 90 and standard deviation = 15. A researcher suspects that the mean for female students is higher than 90. She takes an SRS of 25 female students and gives PSI. Suppose we know that scores in the population of female students are normally distributed with standard deviation = 15.
(a) State the null and alternative hypotheses for the study of female students. (1 pt)
(b) Suppose that the sample mean of 25 students is 91.5. What would be the test statistic Z?