Assume that the mean IQ for all 10th graders at a large high school (i.e., population) is 100 with σ = 15 and that the students are assigned at random to classes with an N of 25.

a. What is the z score for a class whose IQ averages 104? What is the one-tailed p value for this z score? What is the two-tailed p?

b. Repeat part (a) for a class whose mean IQ is 92.

c. Perform two-tailed null hypothesis tests for the classes in part (a) and part (b) at both the .05 and .01 levels.

In each case explain whether you could be making a Type I or Type II error.