QUESTION 1

Which statement(s) about the standard error of the mean is(are) true?

	A.	The standard error of the mean is never larger than the standard deviation of the population.
	B.	The standard error of the mean decreases as the sample size increases.
	C.	The standard error of the mean measures the variability of the mean from sample to sample.
	D.	All of the above.

4 points

QUESTION 2

What do sampling distributions describe the distribution of?

	A.	Sample
	B.	Parameter
	C.	Sample Size
	D.	Statistic

4 points

QUESTION 3

Major league baseball salaries averaged $3.26 million with a standard deviation of $1.5 million in a recent year. Suppose a sample of 100 major league players wastaken. What was the standard error for the sample mean salary?

	A.	$15 milion
	B.	$0.15 milion
	C.	$0.015 milion
	D.	$150 milion

4 points

QUESTION 4

An 95% confidence interval for the average salary of all CEOs in the electronics industry was constructed using the results of a random survey of 45 CEOs. The interval was ($139,134,$154,365). To make more useful inferences from the data, it is desired to reduce the width of the confidence interval. Which of the following will resulting a narrower confidence interval for sure?

	A.	Increase the sample size and increase the confidence level
	B.	Increase the sample size and decrease the confidence level
	C.	Decrease the sample size and increase the confidence level
	D.	Decrease the sample size and decrease the confidence level

4 points

QUESTION 5

Which statement best describes why the Central Limit Theorem is important in statistics?

	A.	For any population, it says the sampling distribution of the sample mean is approximately normal, regardless of the sample size.
	B.	For a large n, it says the population is approximately normal.
	C.	For a large n, it says the sampling distribution of the sample mean is approximately normal, regardless of the shape of the population.
	D.	For any sized sample, it says the sampling distribution of the sample mean is approximately normal.

4 points

QUESTION 6

In a random sample of 2000 small business, it is found that 1400 were "successful". Based on this information, what is an estimator of p, the true proportion ofsmall business that are successful?

	A.	75%
	B.	70%
	C.	55%
	D.	80%

4 points

QUESTION 7

It is desired to estimate the mean total compensation of CEOs in the Service industry. Data were randomly collected from 45 CEOs and the 95% confidenceinterval was calculated to be ($139,134,$154,365). Which of the following interpretations is correct?

	A.	In the population of Service industry CEOs, 95% of them will have total compensations that fall in the interval $139,134 to $154,365.
	B.	We are 95% confident that the mean of the sampled CEOs falls in the interval $139,134 to $154,365.
	C.	We are 95% confident that the mean total compensation of all CEOs in the Service industry falls in the interval $139,134 to $154,365.
	D.	95% of the sampled total compensation values fell between $139,134 to $154,365.

4 points

QUESTION 8

If the sample mean is 102,the population standard deviation is 14, and the sample size is 63,construct a 99%confidence interval of the population mean.

	A.	[97.46, 106.54]
	B.	[95.16, 105.34]
	C.	[98.54, 105.46]
	D.	[99.10, 104.90]

4 points

QUESTION 9

National Science Foundation is estimating the average total salary of full professors in the math department. Data were randomly collected from 20 professors and the 95% confidenceinterval for the mean was calculated to be ($95,201, $108,030). What additional assumption is necessary for this confidenceinterval to be valid?

	A.	None. The Central Limit Theorem applies.
	B.	The sample standard deviation is less than the degrees of freedom.
	C.	The population of total salaries of full professors in math is approximately normally distributed.
	D.	The distribution of the sample means is approximately normal.

4 points

QUESTION 10

19A telecommunication company wants to estimate the proportion of households that would purchase an additional telephone line if it were made available at a substantially reduced installation cost. Data are collected from a random sample of 500 households. The results indicate that 160 of the households would purchase the additional telephone line at a reduced installation cost. Construct a 95% confidence interval for the population proportion of households that would purchase the additional telephone line.

	A.	[0.279, 0.361]
	B.	[0.286, 0.354]
	C.	[0.271, 0.369]
	D.	[0.271, 0.354]