Which of the following is equal to the expression listed below? 45 + 18
A. (9 +5)(9+2)
B. 9+ (5 x 2)
C. (9 x 5)(9 x 2)
D. 9(5+2)

Arandom sample of n = 25 observations is taken from a n(µ, σ ) population. a 95% confidence interval for µ was calculated to be (42.16, 57.84). the researcher feels that this interval is too wide. you want to reduce the interval to a width at most 12 units. a) for a confidence level of 95%, calculate the smallest sample size needed. b) for a sample size fixed at n = 25, calculate the largest confidence level 100(1 − α)% needed.