題組內容

2. (15%) Consider a random sample of size 20 from a normal distribution, $X_i \sim N(\mu, \sigma^2)$, and suppose that $\bar{x} = 11$ and $s^2 = 16$.

(c) What sample size is needed in order for the power of the test to be 0.90 for the alternative value $\mu = 10.5$?