5. You form a distribution of the means of all samples of size 9 drawn from an infinite population that is skewed to the left. The population from which the samples are drawn has a mean of 50 and a standard deviation of 12. Which one of the following statements is true of this sampling distribution? (a) µz = 50, ơ, = 12 , the sampling distribution is skewed somewhat to the left. (b) u, = 50, ơ, = 4, the sampling distribution is skewed somewhat to the left. (c) u, = 50, o, =12 , the sampling distribution is approximately normal. (d) µ, = 50, o, = 4 , the sampling distribution is approximately normal.

4. A distribution of scores has = 70.  The z-score for X = 65 is computed and a value of z = +1.00.  Regardless of the value of the standard deviation, why must this z-score be incorrect?

The weight in kilograms of the citizens of Fredonia has a mean of 50 kg and standard deviation of 24 kg (a) Find the mean of the sampling distribution of the sample mean. (b) Find the standard deviation of the sampling distribution of the sample mean.

4. A normal population has the mean of 20 and the variance of 100. A random sample of size n = 69 is selected. (a) Find the standard deviation of the sample mean. (b) How large must the sample be if you want to halve the standard deviation of the sample mean?

5. On an examination the average grade was 74 and the standard deviation was 7. If 12% of the class are given A's, and the grades are curved to follow normal distribution, what is the lowest possible A and the highest possible B? P(Z < = 1-0.12 = 0.88 1o nou X1 - 74 X1 = 7

In a population of a certain species of newt, the mean length of the newts is μ= 63 inches and the standard deviation is σ= 3.4 inches. You collect a random sample of n=16 newts. The bell curve below represents the distribution of these sample means. The scale on the horizontal axis is the standard error of the sampling distribution. Complete the indicated boxes, correct to two decimal places. mean of distribution= standard error=       Note: The left box is 2 standard errors below the mean. The middle box is the mean. The right box is 2 standard errors above the mean.

This Is A REVIEW! Please help and show work on paper

ou should complete the table as part of the procedure of finding the variance and standard deviation.   Xi           (Xi-(mu))       | (Xi-(mu)) | 49    53    60    60    62    63    64    69    73    87      [Note, this is the same set of data points used in problem 6. How does this compare to the standard deviation computed in problem 6?  Why might this be smaller?]

5. The distribution of heights of a certain breed of terrier has a mean of 72 centimeters and a standard deviation of 10 centimeters, whereas the distribution of heights of a certain breed of poodle has a mcan of 28 centimeters with a standard deviation of 5 centimcters. Assume the distributions of both types of breeds are normally distributed. (n) Suppose we are taking a random sample of 64 terriers. What is the sampling distri- bution of mean heights of the breed of terriers? (b) Find the probability that the sample mean for a random sample of heights of 61 terriers excoedls 75 centimetcrs. (c) Find the probability that the sample mean for a random sample of heights of 64 terriers excoeds the sample mean for a random sample of heights of 100 poodles by at lenst 44.2 centimeters.