Can you please show formulas and work?

LO8 3. A sample of n = 4 scores is selected from a population with an unknown mean. The sample has a mean of M = 40 and a variance of s = 16. Which of the following is the correct 90% confidence interval for u? a. u = 40 + 2.353(4) b. u = 40 + 1.638(4) C. = 40 + 2.353(2) d. u = 40 + 1.638(2) LO9 4. A researcher uses a sample of n = 25 individuals to evaluate the effect of a