Mean Family Size. Use the following information for Exercises 72–74: According to the Statistical Abstract of the United States, the mean family size in 2010 was 3.14 persons, reflecting a slow decrease since 1980, when the mean family size was 3.29 persons. Has this trend continued to the present day? Suppose a random sample of 225 families taken this year yields a sample mean size of 3.05 persons, and suppose we assume that the population standard deviation of family sizes is 1 person.
73. Refer to Exercise 72.
9.3.73
(a) 0 (b) Type II error; Type I error (c) This headline is not supported by the data and our hypothesis test.