7.2. (a) The null hypothesis is H0: μ = 20, and the alternative hypothesis is H1: μ ≠ 20. (b) The test statistic is t = (25 - 20) / (5 / √n) = 2.236.
5.2. (a) The z-score of X = 12 is z = (12 - 10) / 2 = 1. (b) The probability that X is less than 12 is P(X < 12) = P(Z < 1) = 0.8413. all of statistics larry solutions manual full
6.1. (a) A confidence interval is a range of values within which a population parameter is likely to lie. (b) A 95% confidence interval for the mean is a range of values within which the population mean is likely to lie with probability 0.95. 12) = P(Z <