You want to determine if your widgets from machine 1 are the same as machine 2. Machine 1 has a sample mean of 50 and a population standard deviation of 5 and a sample size of 25. Machine 2 has a sample mean of 52 and a population standard deviation of 6 with a sample size of 12. With an alpha of .01, Which of the following statements are true?

a. We can use 2.58 and -2.58 (or 2.57 and -2.57) as our critical values

b. We will use a z test.

c. we use 1.28 and -1.28 (or 1.27 and -1.27) as our critical values

d. A and B are correct

e. None of the above are correct