A carpet company advertises that it will deliver your carpetwithin 15 days of purchase. A sample of 49 past customers is taken.The average delivery time in the sample was 16.2 days. Assume thepopulation standard deviation is known to be 5.6 days.
- State the null and alternative hypotheses.
- t-test or z-test?
- Calculate test statistic
- Using a critical value, test the null hypothesis at the 5%level of significance. State conclusion.
In the past the average age of employees of a large corporationhas been 40 years. Recently, the company has been hiring olderindividuals. In order to determine whether there has been anincrease in the average age of all the employees, a sample of 25employees was selected. The average age in the sample was 45 yearswith a standard deviation of 5 years. Assume the distribution ofthe population is normal. Let a = .05.
- State the null and the alternative hypotheses.
- z-test or t-test?
- Test to determine whether or not the mean age of all employeesis significantly more than 40 years (You may pick which method).State conclusion in a full sentence.
