Joanie decides to buy matching sweaters for herself and her 3 sisters. the regular price of the sweaters is $37. joanie says if she buys four sweaters, two at the regular price and two on sale, she will save 40% off the total cost of the four sweaters at their regular price. is joanie correct?

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.