Which of the following shows 3 + (x + 6y) rewritten using the Associative Property of Addition? 3 + x + 6y 3x + (6 + y) x + (3 + 6y) (3 + x) + 6y

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.