Question

ome he proportion of adult women in the United States is approximately 51%. A marketing survey telephones 300 people at random. (a) (3pts) What is the sampling distribution of the observed proportion that are women? State your answer with the mean and the standard deviation. 30 o (b) (3pts) would you be surprised to find 56% women in a sample of size 300? Explain. (c) (2 pts) What is the probability that more than S0% women in this survey? (d) (2pts) What is the probability that there were fewer than 180 women in the sample? (e) (2pts) What is the probability that there were between 125 and 200 women in the sample? Human gestation times have a mean of about 266 days with a standard deviation of about 16 days. Suppose we look at the mean gestation times for many samples of 150 women. Image all the possible values of the sample mean from many random samples of 150 women. 2. (a) (2pts) If we made the histogram of all these sample means, what shape would it have? (b) (2pts) What is the probability that a sample of 150 women has a mean gestation time of 250 days or less? (c) (2pts) What is the probability that a sample of 150 women has a mean gestation time of 270 days or more? (d) (3pts) What is the number of days in the gestation time for a sample of 150 women if percentile? you want to know t he 80

Answer 1

ρ=0.51 , n=300 0.51x0.49 300 PC-P 二10.0289 P ( 70.50 O 0289 30 D

0.6-0,ら! O.0289 P 125 30O 3Od 0.0299 op