Assume that the heights of women are normally distributed with a mean of 63.5 inches and a standard deviation of 2.5 inches.

Find Q₃, the third quartile that separates the bottom 75% from the top 25%.

a. 66.4

b. 65.2

c. 66.7

d. 61.8

For the population of one town, the number of siblings, x, is a random variable whose relative frequency histogram has a reverse J-shape. The mean number of siblings is 1.3 and the standard deviation is 1.4.

Let denote the mean number of siblings for a random sample of size 30. Determine the sampling distribution of the mean for samples of size 30,and give its mean and standard deviation.

a. Approximately normal, mean = 1.3, standard deviation = 1.4

b. Normal, mean = 1.3, standard deviation = 1.4

c. Approximately normal, mean = 1.3, standard deviation = 0.26

d. Normal, mean = 1.3, standard deviation = 0.26

The mean weight of loads of rock is 45.0 tons with a standard deviation of 12.0 tons. If 16 loads are chosen at random for a weight check, find the probability that the mean weight of those loads is less than 42.00 tons. Assume that the variable is normally distributed.

a. 0.1587

b. 0.3987

c. 0.2067

d. 0.5016