# Question

The article “Unmarried Couples More Likely to Be Interracial” (San Luis Obispo Tribune, March 13, 2002) reported that 7% of married couples in the United States are mixed racially or ethnically. Consider the population consisting of all married couples in the United States.

a. A random sample of n = 100 couples will be selected from this population and p^ , the proportion of couples that are mixed racially or ethnically, will be computed. What are the mean and standard deviation of the sampling distribution of p^ ?

b. Is it reasonable to assume that the sampling distribution of p^ is approximately normal for random samples of size n = 100? Explain. np , 10.

c. Suppose that the sample size is n = 200 rather than n = 100, as in Part (b). Does the change in sample size change the mean and standard deviation of the sampling distribution of p^? If so, what are the new values for the mean and standard deviation? If not, explain why not.

d. Is it reasonable to assume that the sampling distribution of p^ is approximately normal for random samples of size n = 200? Explain.

e. When n = 200, what is the probability that the proportion of couples in the sample who are racially or ethnically mixed will be greater than .10?

a. A random sample of n = 100 couples will be selected from this population and p^ , the proportion of couples that are mixed racially or ethnically, will be computed. What are the mean and standard deviation of the sampling distribution of p^ ?

b. Is it reasonable to assume that the sampling distribution of p^ is approximately normal for random samples of size n = 100? Explain. np , 10.

c. Suppose that the sample size is n = 200 rather than n = 100, as in Part (b). Does the change in sample size change the mean and standard deviation of the sampling distribution of p^? If so, what are the new values for the mean and standard deviation? If not, explain why not.

d. Is it reasonable to assume that the sampling distribution of p^ is approximately normal for random samples of size n = 200? Explain.

e. When n = 200, what is the probability that the proportion of couples in the sample who are racially or ethnically mixed will be greater than .10?

## Answer to relevant Questions

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