10 16 A random sample of 250 observations is taken from population A which has 30 of its population living in poverty A 3 A second random sample of size 350 is taken indepen dently taken from population B which has 15 of its population living in poverty TB 15 a What are the mean and standard deviation of the difference in the sample propor tions A B b Describe the shape of the sampling distribution of the difference in the sample proportions A B c Is it appropriate to use the normal approximation to the sampling distribution of the difference in the sample proportions A B 10 17 Refer to Exercise 10 16 Assuming that equal sample sizes will be taken from the two popu lations how large a sample should be taken from each of the populations to obtain a 99 confi dence interval for TA TB with a width of at most 02 Hint Use A 3 and B 15 from Exercise 10 16