An SRS of 100 postal empl

An SRS of 100 postal empl

An SRS of 100 postal employees found that the average time these employees had worked for the postal service was 7 years, with a standard deviation of 2 years. Assume the distribution of the time the population of employees has worked for the postal service is approximately normal, with mean u. Are these data evidence that u has changed fom the value of 7.5 years of 20 years ago? To determine this, we test the hypotheses Ho: u=7.5, Ha not equal to 7.5 using the one-sample test 1. Suppose the mean and standard deviation obtained were based on a sample of 25 postal workers rather than 100. The P-value would be: a) larger b) smaller c) unchanged because the difference between x-bar and the hypothesized value u=7.5 is unchanged d) unchanged because the variability measured by the standard deviation stays the same 2. A 95% confidence interval for the population mean time u that postal service employees have spent with the postal service is: a) 7 +or- 2 b) 7 +or- 1.984 c) 7 +or- 0.4 d) 7 +or- 0.2 How do you solve these?

%d bloggers like this: