At the end of each quarter, $3,500 is placed in an annuity that earns 8% compounded quarterly. Find the interest earned in 7 years. A. $129,679.24
B. $32,272.81
C. $31,679.24
D. $31,675.24

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.