Question 1

The sample size needed to estimate a population mean within 1.5 units with a 95% confidence when the population standard deviation equals 10 is:

Accepted Answer

A)  121 
B)  13 
C)  171 
D)  54 
E)  88 
A)  121 
B)  13 
C)  171 
D)  54 
E)  88

Question 2

A point estimate is a single number that is used as an estimate of a population parameter or population characteristic. It is usually derived from a random sample from the population of interest.

Accepted Answer

A) True 
 B)False

Question 3

A laboratory technician is interested in the proportion of 1-liter containers used in the lab that are glass. How many containers should be sampled in order to estimate this proportion with a margin of error of less than 0.2 with 99% confidence?
______________

Accepted Answer

The answer of A laboratory technician is interested in the...

Question 4

After constructing a confidence interval estimate for a population mean, you believe that the interval is useless because it is too wide. In order to correct this problem, you need to:

Accepted Answer

A)  increase the population size 
B)  increase the sample mean 
C)  increase the confidence coefficient 
D)  increase the sample size 
E)  decrease the sample size 
A)  increase the population size 
B)  increase the sample mean 
C)  increase the confidence coefficient 
D)  increase the sample size 
E)  decrease the sample size

Question 5

If the population deviation   is known and we wish to estimate the population mean   with 90% confidence, what is the appropriate critical value z to use?

Accepted Answer

A)  1.28 
B)  1.645 
C)  1.96 
D)  2.33 
E)  2.58 
A)  1.28 
B)  1.645 
C)  1.96 
D)  2.33 
E)  2.58

Question 6

Assume that the population standard deviation of annual incomes of all Michigan residents is $2,500. How many individuals must we include in a simple random sample if we want to be 95% confident that the population mean incomes lies within $150 of our sample mean income?
______________

Accepted Answer

The answer of Assume that the population standard deviation of...

Question 7

Two independent random samples of sizes   and   have been selected from binomial populations with parameters   and   , respectively, and resulted in 38 and 65 success, respectively. Then, the point estimation of the difference   is -27.

Accepted Answer

A) True 
 B)False

Question 8

The meat department of a local supermarket packages ground beef using meat trays of two sizes: one designed to hold approximately 1.5 pounds of meat, and one that holds approximately 3 pounds. A random sample of 36 packages in the smaller meat trays produced weight measurements with an average of 1.51 pounds and a standard deviation of 0.20 pound.
Construct a 99% confidence interval for the average weight of all packages sold in the small meat trays by this supermarket chain.
______________
What does the phrase "99% confident" mean?
________________________________________________________
Suppose that the quality control department of this supermarket chain intends that the amount of ground beef in the smaller trays should be 1.5 pound on average. Should the confidence interval in part (a) concern the quality control department?
______________
Explain.
________________________________________________________

Accepted Answer

(1.4242, 1.5958); In repeated sampling,

Question 9

A 99% confidence interval estimate for a population mean   is determined to be 85.58 to 96.62. If the confidence level is reduced to 90%, the confidence interval for   :

Accepted Answer

A)  becomes wider 
B)  remains the same 
C)  becomes narrower 
D)  becomes wider on the left but remains the same on the right 
E)  does none of these 
A)  becomes wider 
B)  remains the same 
C)  becomes narrower 
D)  becomes wider on the left but remains the same on the right 
E)  does none of these

Question 10

The z-value needed to construct a 92.5% confidence interval estimate for the difference between two population proportions is:

Accepted Answer

A)  2.58 
B)  2.33 
C)  1.96 
D)  1.78 
E)  1.33 
A)  2.58 
B)  2.33 
C)  1.96 
D)  1.78 
E)  1.33

Question 11

The margin of error equals the sum of an estimator's squared bias plus its variance.

Accepted Answer

A) True 
 B)False

Question 12

A 99% upper confidence bound (UCB) for the difference between population means in case of large samples (both   and   greater than 30) can be constructed using the following equation:
UCB =

Accepted Answer

A) True 
 B)False

Question 13

A confidence interval for the population mean   will contain the true value of   as long as the point estimate   is within the lower and the upper confidence limits.

Accepted Answer

A) True 
 B)False

Question 14

Which of the following statements is true with respect to a point estimate?

Accepted Answer

A)  It is subject to sampling error and will almost always be different from the true value of the population parameter. 
B)  It is a population parameter. 
C)  It is the upper value of an interval estimate. 
D)  Neither it is subject to sampling error and will almost always be different from the true value of the population parameter nor it is a population parameter. 
E)  Both it is subject to sampling error and will almost always be different from the true value of the population parameter and it is a population parameter. 
A)  It is subject to sampling error and will almost always be different from the true value of the population parameter. 
B)  It is a population parameter. 
C)  It is the upper value of an interval estimate. 
D)  Neither it is subject to sampling error and will almost always be different from the true value of the population parameter nor it is a population parameter. 
E)  Both it is subject to sampling error and will almost always be different from the true value of the population parameter and it is a population parameter.

Question 15

In estimating the difference between two population means, if a 90% confidence interval estimate includes zero, then we can conclude that there is a 90% chance that the difference between the two population means is zero.

Accepted Answer

A) True 
 B)False

Question 16

The lower limit of the 90% confidence interval for the population proportion p, given that n = 400; and   = 0.10, is 0.1247.

Accepted Answer

A) True 
 B)False

Question 17

The z-value needed to construct a 97.8% confidence interval estimate for the difference between two population proportions is:

Accepted Answer

A)  2.33 
B)  2.29 
C)  2.02 
D)  1.96 
E)  1.65 
A)  2.33 
B)  2.29 
C)  2.02 
D)  1.96 
E)  1.65

Question 18

An estimator is unbiased if the mean of its sampling distribution is the population parameter being estimated.

Accepted Answer

A) True 
 B)False

Question 19

The standard error of the sampling distribution of   is given by the formula:
SE =   .

Accepted Answer

A) True 
 B)False

Question 20

The best estimator of the difference between two population means   is the difference between two sample means   .

Accepted Answer

A) True 
 B)False

The sample size needed to estimate a population mean within 1.5 units with a 95% confidence when the population standard deviation equals 10 is:

A point estimate is a single number that is used as an estimate of a population parameter or population characteristic. It is usually derived from a random sample from the population of interest.

A laboratory technician is interested in the proportion of 1-liter containers used in the lab that are glass. How many containers should be sampled in order to estimate this proportion with a margin of error of less than 0.2 with 99% confidence? ______________

After constructing a confidence interval estimate for a population mean, you believe that the interval is useless because it is too wide. In order to correct this problem, you need to:

If the population deviation is known and we wish to estimate the population mean with 90% confidence, what is the appropriate critical value z to use?

Assume that the population standard deviation of annual incomes of all Michigan residents is $2,500. How many individuals must we include in a simple random sample if we want to be 95% confident that the population mean incomes lies within $150 of our sample mean income? ______________

Two independent random samples of sizes and have been selected from binomial populations with parameters and , respectively, and resulted in 38 and 65 success, respectively. Then, the point estimation of the difference is -27.

A 99% confidence interval estimate for a population mean is determined to be 85.58 to 96.62. If the confidence level is reduced to 90%, the confidence interval for :

The z-value needed to construct a 92.5% confidence interval estimate for the difference between two population proportions is:

The margin of error equals the sum of an estimator's squared bias plus its variance.

A 99% upper confidence bound (UCB) for the difference between population means in case of large samples (both and greater than 30) can be constructed using the following equation: UCB =

A confidence interval for the population mean will contain the true value of as long as the point estimate is within the lower and the upper confidence limits.

Which of the following statements is true with respect to a point estimate?

In estimating the difference between two population means, if a 90% confidence interval estimate includes zero, then we can conclude that there is a 90% chance that the difference between the two population means is zero.

The lower limit of the 90% confidence interval for the population proportion p, given that n = 400; and = 0.10, is 0.1247.

The z-value needed to construct a 97.8% confidence interval estimate for the difference between two population proportions is:

An estimator is unbiased if the mean of its sampling distribution is the population parameter being estimated.

The standard error of the sampling distribution of is given by the formula: SE = .

The best estimator of the difference between two population means is the difference between two sample means .

Describing Data With Graphs

Describing Data With Numerical Measures

Describing Bivariate Data

Probability and Probability Distributions

Several Useful Discrete Distributions

The Normal Probability Distribution

Sampling Distributions

Large-Sample Tests of Hypotheses

Inference From Small Samples

The Analysis of Variance

Linear Regression and Correlation

Multiple Regression Analysis

Analysis of Categorical Data

Nonparametric Statistics

Filters

Exam 8: Large-Sample Estimation

The sample size needed to estimate a population mean within 1.5 units with a 95% confidence when the population standard deviation equals 10 is:

A point estimate is a single number that is used as an estimate of a population parameter or population characteristic. It is usually derived from a random sample from the population of interest.

A laboratory technician is interested in the proportion of 1-liter containers used in the lab that are glass. How many containers should be sampled in order to estimate this proportion with a margin of error of less than 0.2 with 99% confidence? ______________

After constructing a confidence interval estimate for a population mean, you believe that the interval is useless because it is too wide. In order to correct this problem, you need to:

If the population deviation is known and we wish to estimate the population mean with 90% confidence, what is the appropriate critical value z to use?

Assume that the population standard deviation of annual incomes of all Michigan residents is $2,500. How many individuals must we include in a simple random sample if we want to be 95% confident that the population mean incomes lies within $150 of our sample mean income? ______________

Two independent random samples of sizes and have been selected from binomial populations with parameters and , respectively, and resulted in 38 and 65 success, respectively. Then, the point estimation of the difference is -27.

A 99% confidence interval estimate for a population mean is determined to be 85.58 to 96.62. If the confidence level is reduced to 90%, the confidence interval for :

The z-value needed to construct a 92.5% confidence interval estimate for the difference between two population proportions is:

The margin of error equals the sum of an estimator's squared bias plus its variance.

A 99% upper confidence bound (UCB) for the difference between population means in case of large samples (both and greater than 30) can be constructed using the following equation: UCB =

A confidence interval for the population mean will contain the true value of as long as the point estimate is within the lower and the upper confidence limits.

Which of the following statements is true with respect to a point estimate?

In estimating the difference between two population means, if a 90% confidence interval estimate includes zero, then we can conclude that there is a 90% chance that the difference between the two population means is zero.

The lower limit of the 90% confidence interval for the population proportion p, given that n = 400; and = 0.10, is 0.1247.

The z-value needed to construct a 97.8% confidence interval estimate for the difference between two population proportions is:

An estimator is unbiased if the mean of its sampling distribution is the population parameter being estimated.

The standard error of the sampling distribution of is given by the formula: SE = .

The best estimator of the difference between two population means is the difference between two sample means .

Describing Data With Graphs

Describing Data With Numerical Measures

Describing Bivariate Data

Probability and Probability Distributions

Several Useful Discrete Distributions

The Normal Probability Distribution

Sampling Distributions

Large-Sample Tests of Hypotheses

Inference From Small Samples

The Analysis of Variance

Linear Regression and Correlation

Multiple Regression Analysis

Analysis of Categorical Data

Nonparametric Statistics

Filters