4 If P(Z

4 If < 1.645) 0.95, follow the steps as in the lecture (i.e., start from the probability for standard normal random variable) to show that X 1.645 is a Cl for the population mean, g. Assume a SRS, is drawn where the underlying mean is and the variance o . 5 A simple random sample (SRS) of size 100 has X 6 and s = 1.5. (a) Give a Cl for 1/ _ (b) Find the samplc size required to estimate within 0.1 for 95% of thc time. 6 In a random sample of 100 customers of a high-speed internet provider, 40 said that their sewice had been interrupted one or more times in the past month. (a) Find a Cl for the proportion of customers whuse service was interrupted one or more times in the past month. (b) Find the sample size needed for a 95% Cl to specify the proportion within +0.05.