Scores on the Scholastic Aptitude Test are normally distributed with μ = 500 and o= 100. Suppose we randomly select 20 persons from the population of all persons who take the test and compute the sample mean, A. What is the standard deviation of the sampling distribution of ? B. What will be the shape of the sampling distribution of ? e. What is the probability that the sample mean, will be greater than 560?

Suppose that the distance of fly balls hit to the outfield (in baseball) is normally distributed with a mean of 268 feet and a standard deviation of 43 feet. Let X be the distance in feet for a fly ball. a. What is the distribution of X? X - N( b. Find the probability that a randomly hit fly ball travels less than 219 feet. Round to 4 decimal places. c. Find the 75th percentile for the distribution of distance of fly balls. Round to 2 decimal places. feet

A population has a mean = 73 and a standard deviation σ = 22. Find the mean and standard deviation of a sampling distribution of sample means with sample size n=240. 1x = (Simplify your answer.)

Suppose that the average number of Facebook friends users have is normally distributed with a mean of 111 and a standard deviation of about 59. Assume fourteen individuals are randomly chosen. Answer the following questions. Round all answers to 4 decimal places where possible. a. What is the distribution of æ? ¤ - N( b. For the group of 14, find the probability that the average number of friends is more than 94. c. Find the first quartile for the average number of Facebook friends. d. For part b), is the assumption that the distribution is normal necessary? Yes No Submit Question logi F2 F5 3 R. T. *CO 8 7 6

A population has a mean µ = 87 and a standard deviation o=27. Find the mean and standard deviation of a sampling distribution of sample means with sample size n = 81. (Simplify your answer.)

Suppose that the number of Facebook friends users have is normally distributed with a mean of 149 and a standard deviation of about 41. Assume fifteen individuals are randomly chosen. Answer the following questions. Round all answers to 4 decimal places where possible. a.  What is the distribution of x̄? x̄ - N  -----------, ---------- b.  For the group of 15, find the probability that the average number of friends is less than 156. ------------- c.  Find the first quartile for the average number of Facebook friends. Round to 2 decimals places. --------------- d.  For part b), is the assumption that the distribution is normal necessary?  ------------No, --------- yes

The mean weight of 1000 students at a certain high school is 140 pounds and the standard deviation of 10 pounds. Assuming that the weights are normally distributed. How many students weigh more than 150 pounds? Select one: O 342.3 O 343.3 O 341.3 O 344.3

Assume a population of 3, 4, and 11. Assume that samples of size n = 2 are randomly selected with replacement from the population. Listed below are the nine different samples. Complete parts a through d below. 3,4 3,3 a. Find the value of the population standard deviation o. S ▼ 3,11 ▼ ■ 1 | 4,3 4,4 C (Round to three decimal places as needed.) b. Find the standard deviation of each of the nine samples, then summarize the sampling distribution of the standard deviations in the format of a table representing the probability distribution of the distinct standard deviation values. Use ascending order of the sample standard deviations. Probability (Type integers or fractions.) c. Find the mean of the sampling distribution of the sample standard deviations. The mean of the sampling distribution of the sample standard deviations is. 4,11 11,3 11,4 11,11