Sociologists classify kin groups by the number of persons living in the same household. A married couple with two children is a kin group of size 4. A person living alone is a min group of size 1. Suppose that 25 randomly selected households are examined and the mean kin-group size for the sample is found to be 3.28 and the standard deviation is 0.85
a) Assuming kin-group size ins approximately normally distributed, construct an 80% confidence interval for the population mean kin-group size
b) It has been claimed that the population variance of kin-group sizes is less than 1. Formulate and test the appropriate hypotheses at a 5% level of significance. Use the critical value approach