Multiple Choice Test. 1. Which of the following is true about the sampling distribution of the sample mean? a) The mean of the sampling distribution

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Multiple Choice Test.

1. Which of the following is true about the sampling distribution of the sample mean?

a) The mean of the sampling distribution is always .

b) The standard deviation of the sampling distribution is always .

c) The shape of the sampling distribution is always approximately normal.

d) All of the above are true.

2. Sales prices of baseball cards from the 1960s are known to possess a skewed-right distribution with a mean sale price of $5.25 and a standard deviation of $2.80. Suppose a random sample of 100 cards from the 1960s is selected. Describe the sampling distribution for the sample mean sale price of the selected cards.

a) Skewed-right with a mean of $5.25 and a standard error of $2.80

b) Normal with a mean of $5.25 and a standard error of $0.28

c) Skewed-right with a mean of $5.25 and a standard error of $0.28

d) Normal with a mean of $5.25 and a standard error of $2.80

3. For sample size 16, the sampling distribution of the mean will be approximately normally distributed

a) regardless of the shape of the population.

b) if the shape of the population is symmetrical.

c) if the sample standard deviation is known.

d) if the sample is normally distributed.

4. For sample sizes greater than 30, the sampling distribution of the mean will be approximately normally distributed

a) regardless of the shape of the population.

b) only if the shape of the population is symmetrical.

c) only if the standard deviation of the samples are known.

d) only if the population is normally distributed.

5. Assume the cholesterol levels in a certain population have mean = 200 and standard deviation = 24. The cholesterol levels for a random sample of n = 9 individuals are measured and the sample mean x is determined. What is the z-score for a sample mean (x-bar) = 180?

A. -3.75

B.2.50

C. -2.50

D. 0.83

I. Multiple Choice

1. Suppose a 95% confidence interval for the proportion of Kenyans who exercise regularly is 0.29 to 0.37. Which one of the following statements is FALSE?

A. It is reasonable to say that more than 40% of Kenyans exercise regularly

B. It is reasonable to say that fewer than 40% of Kenyans exercise regularly

C. The hypothesis that 33% of Kenyans exercise regularly cannot be rejected

D. It is reasonable to say that more than 25% of Kenyans exercise regularly

2. Non-sampling error is reduced by

A. Reducing Amount of Data

B. Decreasing Sample Size

C. Increasing Sample Size

D. None of these

3. Any numerical value calculated from sample data is called

A. Error

B. Parameter

C. Statistic

D. Mean

4. Standard deviation of sampling distribution of any statistic is

A. Sampling Error

B. Standard Error

C. Non Sampling Error

D. Type-I Error

5. Any numerical value computed from population is called

A. Bias

B. Sampling Error

C. Parameter

D. Statistic

II.Problem Solving.The number of cars waiting in line at a car wash is distributed as follows:

Number of Cars Probability

00.25

1 0.40

20.20

30.10

40.04

50.01

Using the table of Random numbers (Table 1) select samples from the distribution by assigning as follows:

1. Start in the row corresponding to the day of the month in which you were born.

2. Select two-digit numbers.

3. If you select a random number from 00 to 24, record a length of 0; if from 25 to 64, record a length of 1; if from 65 to 84, record a length of 2; if from 85 to95, record a length of 3; if from 95 to 98, record a length of 4; if it is 99, record a length of 5.Select samples of n = 2, n = 5, and n =10.Compute the mean for each sample.For example, if a sample of size 2 results inrandom numbers 18 and 46, these would correspond to lengths of 0 and 1, respectively, producing a sample mean of 0.5.What conclusions can you reach concerning the sampling distribution of the mean as the sample size is increased.