Understanding Basic Statistics 6th Edition by Charles Henry Brase,Corrinne Pellillo Brase

Exercise 8

For Problems 3-11, please provide the following information:
(a) What is the level of significance State the null and alternate hypotheses.
(b) Find the value of the chi-square statistic for the sample. What are the degrees of freedom Check Requirements What assumptions are you making about the original distribution
(c) Find or estimate the P -value of the sample test statistic.
(d) Based on your answers in parts (a)-(c), will you reject or fail to reject the null hypothesis of independence
(e) Interpret your conclusion in the context of the application.
In each of the following problems, assume a normal population distribution.
Medicine: Clinical Test A new kind of typhoid shot is being developed by a medical research team. The old typhoid shot was known to protect the population for a mean time of 36 months, with a standard deviation of 3 months. To test the time variability of the new shot, a random sample of 23 people were given the new shot. Regular blood tests showed that the sample standard deviation of protection times was 1.9 months. Using a 0.05 level of significance, test the claim that the new typhoid shot has a smaller variance of protection times.