Which of these systems of equations has an infinite number of solutions?
(A)–6c + 11d = 20
– 6c + 11d = 20

(B)-6c + 11d = 20
– 50 + 8d = 22

(C)–6c+1ld = 22
– 50 + 8d = 22

(D)–50 + 8d = 20
– 50 + 8d = 22

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.