Testosterone levels in males assigned at birth are normally distributed with a mean of 679 ng/dL. If we take a random sample of 10 males assigned at birth, what is the probability that the sample mean will be at least 600 ng/dL with a sample standard deviation of 135 ng/dL?

a. 0.05

b. 0.10

c. 0.90

d. 0.95

e. 0.99

A study is conducted to assess the vitamin D levels of online MPH students. In the study, 250 graduate students are randomly selected and the sample mean of vitamin D levels is 41 ng/mL and the sample standard deviation is 16.6 ng/mL. If you were calculating a 95% confidence interval for the true mean of vitamin D, what would be the critical value?

a. 1.970

b. 1.651

c. 3.302

d. 1.051

e. 1.675