Question 1

Which of the following affects the width of a confidence interval?

Accepted Answer

A)  whether the population standard deviation is known 
B)  the sample mean 
C)  the desired level of confidence 
D)  the population mean 
A)  whether the population standard deviation is known 
B)  the sample mean 
C)  the desired level of confidence 
D)  the population mean C

Question 2

Calculate the 99% confidence interval for a sample of N = 28 with a mean   = 13.64 and standard deviation (s) = 5.52.

Accepted Answer

A)  99% CI = 13.64 ± 2.13 
B)  99% CI = 13.64 ± 1.77 
C)  99% CI = 13.64 ± 2.88 
D)  99% CI = 13.64 ± 3.81 
A)  99% CI = 13.64 ± 2.13 
B)  99% CI = 13.64 ± 1.77 
C)  99% CI = 13.64 ± 2.88 
D)  99% CI = 13.64 ± 3.81 C

Question 3

For a variable with   = 333.00, how large should the sample be for a desired 95% confidence interval width of 100?

Accepted Answer

A)  13 
B)  43 
C)  170 
D)  1849 
A)  13 
B)  43 
C)  170 
D)  1849 C

Question 4

Calculate the 95% confidence interval for a sample of N = 21 with a mean   = 73.51 and standard deviation (s) = 13.62.

Accepted Answer

A)  95% CI = 73.51 ± 6.20 
B)  95% CI = 73.51 ± 5.12 
C)  95% CI = 73.51 ± 8.45 
D)  95% CI = 73.51 ± 5.06 
A)  95% CI = 73.51 ± 6.20 
B)  95% CI = 73.51 ± 5.12 
C)  95% CI = 73.51 ± 8.45 
D)  95% CI = 73.51 ± 5.06

Question 5

For a variable with   = 175.00, how large should the sample be for a desired 95% confidence interval width of 50?

Accepted Answer

A)  14 
B)  47 
C)  188 
D)  2209 
A)  14 
B)  47 
C)  188 
D)  2209

Question 6

A confidence interval is ______.

Accepted Answer

A)  a measure of central tendency 
B)  a single value used to estimate an unknown population parameter 
C)  the upper boundary of a confidence interval 
D)  a range or interval of values that has a stated probability of containing an unknown population parameter 
A)  a measure of central tendency 
B)  a single value used to estimate an unknown population parameter 
C)  the upper boundary of a confidence interval 
D)  a range or interval of values that has a stated probability of containing an unknown population parameter

Question 7

Use the formula   to calculate the lower and upper limits of the 95% confidence interval for a sample of N = 12 with a mean   = 6.00 and standard error of the mean   = 1.15.

Accepted Answer

A)  (3.47, 8.53) 
B)  (3.93, 8.07) 
C)  (2.43, 9.57) 
D)  (2.65, 9.35) 
A)  (3.47, 8.53) 
B)  (3.93, 8.07) 
C)  (2.43, 9.57) 
D)  (2.65, 9.35)

Question 8

Calculate the 99% confidence interval for a sample of N = 24 with a mean   = 96.55 and standard deviation (s) = 7.54.

Accepted Answer

A)  99% CI = 96.55 ± 3.19 
B)  99% CI = 96.55 ± 2.64 
C)  99% CI = 96.55 ± 4.32 
D)  99% CI = 96.55 ± 4.55 
A)  99% CI = 96.55 ± 3.19 
B)  99% CI = 96.55 ± 2.64 
C)  99% CI = 96.55 ± 4.32 
D)  99% CI = 96.55 ± 4.55

Question 9

Calculate the 99% confidence interval for a sample of N = 24 with a mean   = 96.55 and standard error of the mean   = 1.54.

Accepted Answer

A)  99% CI = 96.55 ± 3.19 
B)  99% CI = 96.55 ± 2.64 
C)  99% CI = 96.55 ± 4.32 
D)  99% CI = 96.55 ± 4.55 
A)  99% CI = 96.55 ± 3.19 
B)  99% CI = 96.55 ± 2.64 
C)  99% CI = 96.55 ± 4.32 
D)  99% CI = 96.55 ± 4.55

Question 10

Calculate the 95% confidence interval for a sample of N = 30 with a mean   = 7.12 and standard deviation (s) = 3.67.

Accepted Answer

A)  95% CI = 7.12 ± 1.37 
B)  95% CI = 7.12 ± 1.14 
C)  95% CI = 7.12 ± 1.84 
D)  95% CI = 7.12 ± 2.72 
A)  95% CI = 7.12 ± 1.37 
B)  95% CI = 7.12 ± 1.14 
C)  95% CI = 7.12 ± 1.84 
D)  95% CI = 7.12 ± 2.72

Question 11

Calculate the 90% confidence interval for a sample of N = 21 with a mean   = 65.25 and standard error of the mean   = 2.57.

Accepted Answer

A)  90% CI = 65.25 ± 4.43 
B)  90% CI = 65.25 ± 7.31 
C)  90% CI = 65.25 ± 4.30 
D)  90% CI = 65.25 ± 5.36 
A)  90% CI = 65.25 ± 4.43 
B)  90% CI = 65.25 ± 7.31 
C)  90% CI = 65.25 ± 4.30 
D)  90% CI = 65.25 ± 5.36

Question 12

When drawing a conclusion about the 95% confidence interval with a known population standard deviation, a researcher would state that there is a ______.

Accepted Answer

A)  .95 probability that a confidence interval contains the median score for the population 
B)  95% probability that a confidence interval contains the mean score for the population 
C)  .95 probability that a confidence interval contains the mean score for the population 
D)  .05 probability that a confidence interval contains the mean score for the population 
A)  .95 probability that a confidence interval contains the median score for the population 
B)  95% probability that a confidence interval contains the mean score for the population 
C)  .95 probability that a confidence interval contains the mean score for the population 
D)  .05 probability that a confidence interval contains the mean score for the population

Question 13

When a sample size is increased, the confidence interval for the mean is then ______.

Accepted Answer

A)  more significant 
B)  widened 
C)  narrowed 
D)  less significant 
A)  more significant 
B)  widened 
C)  narrowed 
D)  less significant

Question 14

Which confidence interval is the narrowest?

Accepted Answer

A)  99.9% 
B)  99% 
C)  95% 
D)  90% 
A)  99.9% 
B)  99% 
C)  95% 
D)  90%

Question 15

Calculate the 90% confidence interval for a sample of N = 29 with a mean   = 137.98 and standard deviation (s) = 26.84.

Accepted Answer

A)  90% CI = 137.98 ± 8.47 
B)  90% CI = 137.98 ± 13.76 
C)  90% CI = 137.98 ± 6.68 
D)  90% CI = 137.98 ± 10.20 
A)  90% CI = 137.98 ± 8.47 
B)  90% CI = 137.98 ± 13.76 
C)  90% CI = 137.98 ± 6.68 
D)  90% CI = 137.98 ± 10.20

Question 16

Calculate the 90% confidence interval for a sample of N = 17 with a mean   = 18.43 and standard deviation (s) = 2.96.

Accepted Answer

A)  90% CI = 18.43 ± 1.26 
B)  90% CI = 18.43 ± 2.10 
C)  90% CI = 18.43 ± 2.47 
D)  90% CI = 18.43 ± 1.53 
A)  90% CI = 18.43 ± 1.26 
B)  90% CI = 18.43 ± 2.10 
C)  90% CI = 18.43 ± 2.47 
D)  90% CI = 18.43 ± 1.53

Question 17

Calculate the lower and upper limits of the 99% confidence interval for a sample of N = 28 with a mean   = 13.64 and standard error of the mean   = 1.04.

Accepted Answer

A)  (11.51, 15.77) 
B)  (11.87, 15.4) 
C)  (10.76, 16.52) 
D)  (9.83, 17.45) 
A)  (11.51, 15.77) 
B)  (11.87, 15.4) 
C)  (10.76, 16.52) 
D)  (9.83, 17.45)

Question 18

A confidence level of 99% has a higher probability of containing the population mean than does a 95% confidence interval.

Accepted Answer

A) True 
 B)False

Question 19

The ______ the desired width of a confidence interval, the ______ the necessary sample size.

Accepted Answer

A)  larger; larger 
B)  smaller; smaller 
C)  larger; smaller 
D)  smaller; larger 
A)  larger; larger 
B)  smaller; smaller 
C)  larger; smaller 
D)  smaller; larger

Question 20

Calculate the 95% confidence interval for a sample with a mean   = 15.86 and a population standard error of the mean   = 1.89.

Accepted Answer

A)  95% CI = 15.86 ± 3.70 
B)  95% CI = 15.86 ± 3.12 
C)  95% CI = 15.86 ± 4.88 
D)  95% CI = 15.86 ± 3.85 
A)  95% CI = 15.86 ± 3.70 
B)  95% CI = 15.86 ± 3.12 
C)  95% CI = 15.86 ± 4.88 
D)  95% CI = 15.86 ± 3.85

Which of the following affects the width of a confidence interval?

Calculate the 99% confidence interval for a sample of N = 28 with a mean = 13.64 and standard deviation (s) = 5.52.

For a variable with = 333.00, how large should the sample be for a desired 95% confidence interval width of 100?

Calculate the 95% confidence interval for a sample of N = 21 with a mean = 73.51 and standard deviation (s) = 13.62.

For a variable with = 175.00, how large should the sample be for a desired 95% confidence interval width of 50?

A confidence interval is ______.

Use the formula to calculate the lower and upper limits of the 95% confidence interval for a sample of N = 12 with a mean = 6.00 and standard error of the mean = 1.15.

Calculate the 99% confidence interval for a sample of N = 24 with a mean = 96.55 and standard deviation (s) = 7.54.

Calculate the 99% confidence interval for a sample of N = 24 with a mean = 96.55 and standard error of the mean = 1.54.

Calculate the 95% confidence interval for a sample of N = 30 with a mean = 7.12 and standard deviation (s) = 3.67.

Calculate the 90% confidence interval for a sample of N = 21 with a mean = 65.25 and standard error of the mean = 2.57.

When drawing a conclusion about the 95% confidence interval with a known population standard deviation, a researcher would state that there is a ______.

When a sample size is increased, the confidence interval for the mean is then ______.

Which confidence interval is the narrowest?

Calculate the 90% confidence interval for a sample of N = 29 with a mean = 137.98 and standard deviation (s) = 26.84.

Calculate the 90% confidence interval for a sample of N = 17 with a mean = 18.43 and standard deviation (s) = 2.96.

Calculate the lower and upper limits of the 99% confidence interval for a sample of N = 28 with a mean = 13.64 and standard error of the mean = 1.04.

A confidence level of 99% has a higher probability of containing the population mean than does a 95% confidence interval.

The the desired width of a confidence interval, the the necessary sample size.

Calculate the 95% confidence interval for a sample with a mean = 15.86 and a population standard error of the mean = 1.89.

Introduction to Statistics

Examining Data: Tables and Figures

Measures of Central Tendency

Measures of Variability

Normal Distributions

Probability and Hypothesis Testing

Testing One Sample Mean

Testing the Difference Between Two Means

Errors in Hypothesis Testing, Statistical Power, and Effect Size

One-Way Analysis of Variance Anova

Two-Way Analysis of Variance Anova

Correlation

Linear Regression and Multiple Correlation

Chi-Square

Filters

Exam 8: Estimating the Mean of a Population

Which of the following affects the width of a confidence interval?

Calculate the 99% confidence interval for a sample of N = 28 with a mean = 13.64 and standard deviation (s) = 5.52.

For a variable with = 333.00, how large should the sample be for a desired 95% confidence interval width of 100?

Calculate the 95% confidence interval for a sample of N = 21 with a mean = 73.51 and standard deviation (s) = 13.62.

For a variable with = 175.00, how large should the sample be for a desired 95% confidence interval width of 50?

A confidence interval is ______.

Use the formula to calculate the lower and upper limits of the 95% confidence interval for a sample of N = 12 with a mean = 6.00 and standard error of the mean = 1.15.

Calculate the 99% confidence interval for a sample of N = 24 with a mean = 96.55 and standard deviation (s) = 7.54.

Calculate the 99% confidence interval for a sample of N = 24 with a mean = 96.55 and standard error of the mean = 1.54.

Calculate the 95% confidence interval for a sample of N = 30 with a mean = 7.12 and standard deviation (s) = 3.67.

Calculate the 90% confidence interval for a sample of N = 21 with a mean = 65.25 and standard error of the mean = 2.57.

When drawing a conclusion about the 95% confidence interval with a known population standard deviation, a researcher would state that there is a ______.

When a sample size is increased, the confidence interval for the mean is then ______.

Which confidence interval is the narrowest?

Calculate the 90% confidence interval for a sample of N = 29 with a mean = 137.98 and standard deviation (s) = 26.84.

Calculate the 90% confidence interval for a sample of N = 17 with a mean = 18.43 and standard deviation (s) = 2.96.

Calculate the lower and upper limits of the 99% confidence interval for a sample of N = 28 with a mean = 13.64 and standard error of the mean = 1.04.

A confidence level of 99% has a higher probability of containing the population mean than does a 95% confidence interval.

The ______ the desired width of a confidence interval, the ______ the necessary sample size.

Calculate the 95% confidence interval for a sample with a mean = 15.86 and a population standard error of the mean = 1.89.

Introduction to Statistics

Examining Data: Tables and Figures

Measures of Central Tendency

Measures of Variability

Normal Distributions

Probability and Hypothesis Testing

Testing One Sample Mean

Testing the Difference Between Two Means

Errors in Hypothesis Testing, Statistical Power, and Effect Size

One-Way Analysis of Variance Anova

Two-Way Analysis of Variance Anova

Correlation

Linear Regression and Multiple Correlation

Chi-Square

Filters

The the desired width of a confidence interval, the the necessary sample size.