Question 1

For a given confidence level and when σ is known, the margin of error in a confidence interval estimate

Accepted Answer

A)  ​varies from sample to sample of the same size. 
B)  ​is the same for all samples of the same size. 
C)  ​increases as the sample size increases. 
D)  ​is independent of sample size. 
A)  ​varies from sample to sample of the same size. 
B)  ​is the same for all samples of the same size. 
C)  ​increases as the sample size increases. 
D)  ​is independent of sample size.

Question 2

To compute the necessary sample size for an interval estimate of a population mean, all of the following procedures are recommended when σ is unknown except​

Accepted Answer

A)  ​use the estimated σ from a previous study. 
B)  ​use the sample standard deviation from a preliminary sample. 
C)  ​use judgment or a best guess. 
D)  use .5 as an estimate. 
A)  ​use the estimated σ from a previous study. 
B)  ​use the sample standard deviation from a preliminary sample. 
C)  ​use judgment or a best guess. 
D)  use .5 as an estimate.

Question 3

When constructing a confidence interval for the population mean using the standard deviation of the sample, the degrees of freedom for the t distribution equals

Accepted Answer

A)  n - 1. 
B)  n. 
C)  2n. 
D)  n + 1. 
A)  n - 1. 
B)  n. 
C)  2n. 
D)  n + 1.

Question 4

​The margin of error in an interval estimate of the population mean is a function of all of the following except

Accepted Answer

A)  α. 
B)  ​sample mean. 
C)  ​sample size. 
D)  ​variability of the population. 
A)  α. 
B)  ​sample mean. 
C)  ​sample size. 
D)  ​variability of the population.

Question 5

In interval estimation, the t distribution is applicable only when

Accepted Answer

A)  the population has a mean of less than 30. 
B)  the sample standard deviation is used to estimate the population standard deviation. 
C)  the variance of the population is known. 
D)  the mean of the population is unknown. 
A)  the population has a mean of less than 30. 
B)  the sample standard deviation is used to estimate the population standard deviation. 
C)  the variance of the population is known. 
D)  the mean of the population is unknown.

Question 6

​As the degrees of freedom increase, the t distribution approaches the

Accepted Answer

A)  ​uniform distribution. 
B)  ​normal distribution. 
C)  ​exponential distribution. 
D)  ​p distribution. 
A)  ​uniform distribution. 
B)  ​normal distribution. 
C)  ​exponential distribution. 
D)  ​p distribution.

Question 7

The degrees of freedom associated with a t distribution are a function of the​

Accepted Answer

A)  ​area in the upper tail. 
B)  ​sample standard deviation. 
C)  ​confidence coefficient. 
D)  ​sample size. 
A)  ​area in the upper tail. 
B)  ​sample standard deviation. 
C)  ​confidence coefficient. 
D)  ​sample size.

Question 8

If we want to provide a 95% confidence interval for the mean of a population, the confidence coefficient will be

Accepted Answer

A)  .485. 
B)  1.96. 
C)  .95. 
D)  1.645. 
A)  .485. 
B)  1.96. 
C)  .95. 
D)  1.645.

Question 9

It is known that the population variance (σ2) is 144.At 95% confidence, what sample size should be taken so that the margin of error does not exceed 5?

Accepted Answer

A)  22 
B)  23 
C)  24 
D)  25 
A)  22 
B)  23 
C)  24 
D)  25

Question 10

From a population that is not normally distributed and whose standard deviation is not known, a sample of 50 items is selected to develop an interval estimate for µ.Which of the following statements is true?​

Accepted Answer

A)  ​The standard normal distribution can be used. 
B)  ​The t distribution with 50 degrees of freedom must be used. 
C)  ​The t distribution with 49 degrees of freedom must be used. 
D)  ​The sample size must be increased in order to develop an interval estimate. 
A)  ​The standard normal distribution can be used. 
B)  ​The t distribution with 50 degrees of freedom must be used. 
C)  ​The t distribution with 49 degrees of freedom must be used. 
D)  ​The sample size must be increased in order to develop an interval estimate.

Question 11

If we change a 95% confidence interval estimate to a 99% confidence interval estimate, we can expect the

Accepted Answer

A)  width of the confidence interval to increase. 
B)  width of the confidence interval to decrease. 
C)  width of the confidence interval to remain the same. 
D)  sample size to increase. 
A)  width of the confidence interval to increase. 
B)  width of the confidence interval to decrease. 
C)  width of the confidence interval to remain the same. 
D)  sample size to increase.

Question 12

In order to determine an interval for the mean of a population with unknown standard deviation, a sample of 61 items is selected.The mean of the sample is determined to be 23.The associated number of degrees of freedom for reading the t value is

Accepted Answer

A)  22. 
B)  23. 
C)  60. 
D)  61. 
A)  22. 
B)  23. 
C)  60. 
D)  61.

Question 13

A random sample of 49 statistics examinations was taken.The average score, in the sample, was 84 with a variance of 12.25.The 95% confidence interval for the average examination score of the population of the examinations is

Accepted Answer

A)  80.48 to 87.52. 
B)  77.40 to 86.60. 
C)  82.99 to 85.01. 
D)  68.00 to 100.00. 
A)  80.48 to 87.52. 
B)  77.40 to 86.60. 
C)  82.99 to 85.01. 
D)  68.00 to 100.00.

Question 14

A random sample of 64 SAT scores of students applying for merit scholarships showed an average of 1400 with a standard deviation of 240.The 95% confidence interval for the population mean SAT score is

Accepted Answer

A)  1340.06 to 1459.94. 
B)  1341.20 to 1458.80. 
C)  1349.93 to 1450.07. 
D)  1320.32 to 1479.68. 
A)  1340.06 to 1459.94. 
B)  1341.20 to 1458.80. 
C)  1349.93 to 1450.07. 
D)  1320.32 to 1479.68.

Question 15

We are interested in conducting a study to determine the percentage of voters of a state would vote for the incumbent governor.What is the minimum sample size needed to estimate the population proportion with a margin of error of .05 or less at 95% confidence?

Accepted Answer

A)  200. 
B)  100. 
C)  58. 
D)  385. 
A)  200. 
B)  100. 
C)  58. 
D)  385.

Question 16

An estimate of a population parameter that provides an interval of values believed to contain the value of the parameter is known as the

Accepted Answer

A)  confidence level. 
B)  interval estimate. 
C)  margin of error. 
D)  point estimate. 
A)  confidence level. 
B)  interval estimate. 
C)  margin of error. 
D)  point estimate.

Question 17

From a population with a variance of 900, a sample of 225 items is selected.At 95% confidence, the margin of error is

Accepted Answer

A)  15. 
B)  2.0. 
C)  3.92. 
D)  4. 
A)  15. 
B)  2.0. 
C)  3.92. 
D)  4.

Question 18

The value added to and subtracted from a point estimate in order to develop an interval estimate of the population parameter is known as the

Accepted Answer

A)  confidence level. 
B)  margin of error. 
C)  parameter estimate. 
D)  planning value. 
A)  confidence level. 
B)  margin of error. 
C)  parameter estimate. 
D)  planning value.

Question 19

The sample size needed to provide a margin of error of 2 or less with a .95 probability when the population standard deviation equals 11 is

Accepted Answer

A)  10. 
B)  11. 
C)  116. 
D)  117. 
A)  10. 
B)  11. 
C)  116. 
D)  117.

Question 20

The following random sample from a population whose values were normally distributed was collected. 10
8
11
11
​
The 95% confidence interval for μ is

Accepted Answer

A)  8.52 to 11.48. 
B)  7.75 to 12.25. 
C)  9.25 to 10.75. 
D)  8.00 to 10.00. 
A)  8.52 to 11.48. 
B)  7.75 to 12.25. 
C)  9.25 to 10.75. 
D)  8.00 to 10.00.

For a given confidence level and when σ is known, the margin of error in a confidence interval estimate

To compute the necessary sample size for an interval estimate of a population mean, all of the following procedures are recommended when σ is unknown except

When constructing a confidence interval for the population mean using the standard deviation of the sample, the degrees of freedom for the t distribution equals

The margin of error in an interval estimate of the population mean is a function of all of the following except

In interval estimation, the t distribution is applicable only when

As the degrees of freedom increase, the t distribution approaches the

The degrees of freedom associated with a t distribution are a function of the

If we want to provide a 95% confidence interval for the mean of a population, the confidence coefficient will be

It is known that the population variance (σ²) is 144.At 95% confidence, what sample size should be taken so that the margin of error does not exceed 5?

From a population that is not normally distributed and whose standard deviation is not known, a sample of 50 items is selected to develop an interval estimate for µ.Which of the following statements is true?

If we change a 95% confidence interval estimate to a 99% confidence interval estimate, we can expect the

In order to determine an interval for the mean of a population with unknown standard deviation, a sample of 61 items is selected.The mean of the sample is determined to be 23.The associated number of degrees of freedom for reading the t value is

A random sample of 49 statistics examinations was taken.The average score, in the sample, was 84 with a variance of 12.25.The 95% confidence interval for the average examination score of the population of the examinations is

A random sample of 64 SAT scores of students applying for merit scholarships showed an average of 1400 with a standard deviation of 240.The 95% confidence interval for the population mean SAT score is

We are interested in conducting a study to determine the percentage of voters of a state would vote for the incumbent governor.What is the minimum sample size needed to estimate the population proportion with a margin of error of .05 or less at 95% confidence?

An estimate of a population parameter that provides an interval of values believed to contain the value of the parameter is known as the

From a population with a variance of 900, a sample of 225 items is selected.At 95% confidence, the margin of error is

The value added to and subtracted from a point estimate in order to develop an interval estimate of the population parameter is known as the

The sample size needed to provide a margin of error of 2 or less with a .95 probability when the population standard deviation equals 11 is

The following random sample from a population whose values were normally distributed was collected. 10 8 11 11 The 95% confidence interval for μ is

Data and Statistics

Descriptive Statistics: Tabulargraphical

Descriptive Statistics: Numerical

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Hypothesis Tests

Inference About Means and Proportions With Two Populations

Inferences About Population Variances

Comparing Multiple Proportions, Test of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

Simple Linear Regression

Multiple Regression

Filters

Exam 8: Interval Estimation

For a given confidence level and when σ is known, the margin of error in a confidence interval estimate

To compute the necessary sample size for an interval estimate of a population mean, all of the following procedures are recommended when σ is unknown except​

When constructing a confidence interval for the population mean using the standard deviation of the sample, the degrees of freedom for the t distribution equals

​The margin of error in an interval estimate of the population mean is a function of all of the following except

In interval estimation, the t distribution is applicable only when

​As the degrees of freedom increase, the t distribution approaches the

The degrees of freedom associated with a t distribution are a function of the​

If we want to provide a 95% confidence interval for the mean of a population, the confidence coefficient will be

It is known that the population variance (σ2) is 144.At 95% confidence, what sample size should be taken so that the margin of error does not exceed 5?

From a population that is not normally distributed and whose standard deviation is not known, a sample of 50 items is selected to develop an interval estimate for µ.Which of the following statements is true?​

If we change a 95% confidence interval estimate to a 99% confidence interval estimate, we can expect the

In order to determine an interval for the mean of a population with unknown standard deviation, a sample of 61 items is selected.The mean of the sample is determined to be 23.The associated number of degrees of freedom for reading the t value is

A random sample of 49 statistics examinations was taken.The average score, in the sample, was 84 with a variance of 12.25.The 95% confidence interval for the average examination score of the population of the examinations is

A random sample of 64 SAT scores of students applying for merit scholarships showed an average of 1400 with a standard deviation of 240.The 95% confidence interval for the population mean SAT score is

We are interested in conducting a study to determine the percentage of voters of a state would vote for the incumbent governor.What is the minimum sample size needed to estimate the population proportion with a margin of error of .05 or less at 95% confidence?

An estimate of a population parameter that provides an interval of values believed to contain the value of the parameter is known as the

From a population with a variance of 900, a sample of 225 items is selected.At 95% confidence, the margin of error is

The value added to and subtracted from a point estimate in order to develop an interval estimate of the population parameter is known as the

The sample size needed to provide a margin of error of 2 or less with a .95 probability when the population standard deviation equals 11 is

The following random sample from a population whose values were normally distributed was collected. 10 8 11 11 ​ The 95% confidence interval for μ is

Data and Statistics

Descriptive Statistics: Tabulargraphical

Descriptive Statistics: Numerical

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Hypothesis Tests

Inference About Means and Proportions With Two Populations

Inferences About Population Variances

Comparing Multiple Proportions, Test of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

Simple Linear Regression

Multiple Regression

Filters

To compute the necessary sample size for an interval estimate of a population mean, all of the following procedures are recommended when σ is unknown except

The margin of error in an interval estimate of the population mean is a function of all of the following except

As the degrees of freedom increase, the t distribution approaches the

The degrees of freedom associated with a t distribution are a function of the

It is known that the population variance (σ²) is 144.At 95% confidence, what sample size should be taken so that the margin of error does not exceed 5?

From a population that is not normally distributed and whose standard deviation is not known, a sample of 50 items is selected to develop an interval estimate for µ.Which of the following statements is true?

The following random sample from a population whose values were normally distributed was collected. 10 8 11 11 The 95% confidence interval for μ is