1. Determine which of the following relations are functions. Provide detailed explanations for your answers with EXAMPLES A) The relation between students’ ages and the number of credits earned
B) The relationship between time and the of the half-life of a radioactive substance that has a weight of 45g.

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.