You have been asked to determine if two different production processes have different mean numbers of units produced per hour. Process 1 has a mean defined as µ1 and process 2 has a mean defined as µ2. The null and alternative hypotheses are as follows:
H0: µ1 - µ1 = 0
H1: µ1 – µ2 > 0
Use a random sample of 25 observations from process 1 and 28 observations from process 2 and the known variance for process 1 equal to 900 and the known variance for process 2 equal to 1,600. Can you reject the null hypothesis using a probability of Type I error α = 0.05 in each case?
a. The process means are 50 and 60.
b. The difference in process means is 20.
c. The process means are 45 and 50.
d. The difference in process means is 15.