# Question: a A statistics practitioner is in the process of testing

a. A statistics practitioner is in the process of testing to determine whether there is enough evidence to infer that the population mean is different from 180. She calculated the mean and standard deviation of a sample of 200 observations as x̄ = 175 and s = 22. Calculate the value of the test statistic of the test required to determine whether there is enough evidence at the 5% significance level.

b. Repeat part (a) with s = 45.

c. Repeat part (a) with s = 60.

d. Discuss what happens to the t statistic when the standard deviation increases.

b. Repeat part (a) with s = 45.

c. Repeat part (a) with s = 60.

d. Discuss what happens to the t statistic when the standard deviation increases.

**View Solution:**## Answer to relevant Questions

a. Calculate the test statistic when x̄ = 145, s = 50, and n = 100. Use a 5% significance level.H0: µ = 150H1: µ < 150b. Repeat part (a) with x̄ = 140.c. Repeat part (a) with x̄ = 135.d. What happens to the t-statistic ...a. Estimate the population mean with 90% confidence given the following: x̄ = 175, s = 30 and n = 5.b. Repeat part (a) assuming that you know that the population standard deviation is σ = 30.c. Explain why the interval ...A courier service advertises that its average delivery time is less than 6 hours for local deliveries. A random sample of times for 12 deliveries to an address across town was recorded. These data are shown here. Is this ...Traffic congestion seems to worsen each year. This raises the question, how much does roadway congestion cost the United States annually. The Federal Highway Administration’s Highway Performance Monitoring System conducts ...Can we infer that the mean number of hours worked (HRS1) among those working full or part time is greater than 40?Post your question