Average height of hockey players

  Problem 21) A biologist has found the average weight of 12 randomly selected mud turtles to be 8.7 lb with standard deviation 3.6 lb. Find a 90% confidence interval for the population mean weight of all such turtles.

     Problem 22) How tall are college hockey players? The average height has been 68.3 inches. A random sample of 14 hockey players gave a mean height of 69.1 inches. We may assume that x has a normal distribution with = 0.9 inch. Does this indicate that the population mean height is different from 68.3 inches? Use 5% level of significance. a) State the null and the alternate hypothesis. b) Identify the sampling distribution to be used: the standard normal distribution or the Student's t distribution. Find the critical value(s). c) Compute the z or t value of the sample test statistic. d) Find the P value or an interval containing the P value for the sample test statistic. e) Based on your answers to a through d, decide whether or not to reject the null hypothesis at the given significance level. Explain your conclusion in the context of the problem

     Problem 23) Recently the national average yield on municipal bonds has been = 4.19%. A random sample of 16 Arizona municipal bonds gave an average yield of 5.11% with a sample standard deviation s = 1.15%. Does this indicate that the population mean yield for all Arizona municipal bonds is greater than the national average? Use = 0.05. Assume x is normally distributed. a) State the null and the alternate hypothesis. b) Identify the sampling distribution to be used: the standard normal distribution or the Student's t distribution. Find the critical value(s). c) Compute the z or t value of the sample test statistic d) Find the P value or an interval containing the P value for the sample test statistic. e) Based on your answers to a through d, decide whether or not to reject the null hypothesis at the given significance level. Explain your conclusion in the context of the problem.