In 2018, a study was conducted that stated the average salary for males in Kern county was $78,575. Suppose you were hired to determine if the average salary for males has increased since that study was conducted. You randomly sample 105 males from Kern county and you find that their average salary was $79,537. Further assume that the true standard deviation for all salaries is known to be $4,200. Carry out the appropriate hypothesis test at the a = 0.05 level of significance to determine if the average salary for males in Kern county has increased since 2018.

Fran is training for her first marathon, and she wants to know if there is a significant difference between the mean number of miles run each week by group runners and individual runners who are training for marathons. She interviews 42 randomly selected people who train in groups and finds that they run a mean of 47.1 miles per week. Assume that the population standard deviation for group runners is known to be 4.4 miles per week. She also interviews a random sample of 47 people who train on their own and finds that they run a mean of 48.5 miles per week. Assume that the population standard deviation for people who run by themselves is 1.8 miles per week. Test the claim at the 0.01 level of significance. Let group runners training for marathons be Population 1 and let individual runners training for marathons be Population 2.   Step 2 of 3 :   Compute the value of the test statistic. Round your answer to two decimal places.

A sample of 76 female workers and another sample of 48 male workers from a state produced mean weekly earnings of $743.50 for the females and $777.63 for the males. Suppose that the population standard deviations of the weekly earnings are $80.05 for the females and $88.68 for the males. The null hypothesis is that the mean weekly earnings are the same for females and males, while the alternative hypothesis is that the mean weekly earnings for females is less than the mean weekly earnings for males. Directions: • Label your answers with the correct statistical symbols. • If you use the Ti, identify which function and values you used to calculate. If you solve by hand, show all steps 2.5 The significance level for the test is 1%. What is/are the critical value(s)? 2.6. What is the value of the test statistic, rounded to three decimal places? 2.7. What is the p-value for this test, rounded to four decimal places? 2. 8. Using the p-value approach, do you reject or fail to reject the null…

You are interested in studying the average gestational length of pregnancies among African American women in the United States to see if it is different from the rest of the US population. The population mean for gestational length is 39 weeks with a standard deviation of 2 weeks. You take a simple random sample of 22 African American women that gave birth in the last year and find that their mean gestational length is is 38.5 weeks. If you decide to conduct a two-sided test with α = .05. What is the power of this test?