Question 1

If a normal population has parameters μ = 40 and σ = 8, then for a sample size n = 4:

Accepted Answer

A) the standard error of the sample mean is approximately 2. 
B) the standard error of the sample mean is approximately 4. 
C) the standard error of the sample mean is approximately 8. 
D) the standard error of the sample mean is approximately 10. 
A) the standard error of the sample mean is approximately 2. 
B) the standard error of the sample mean is approximately 4. 
C) the standard error of the sample mean is approximately 8. 
D) the standard error of the sample mean is approximately 10.

Question 2

A company wants to estimate the time its trucks take to drive from city A to cityB. The standard deviation is known to be 12 minutes. What sample size is required in order that the error will not exceed ±2 minutes, with 95 percent confidence?

Accepted Answer

A) 12 observations 
B) 139 observations 
C) 36 observations 
D) 129 observations 
A) 12 observations 
B) 139 observations 
C) 36 observations 
D) 129 observations

Question 3

For a sample of size 16, the critical values of chi-square for a 95 percent confidence interval for the population variance are:

Accepted Answer

A) 6.262, 27.49 
B) 6.908, 28.85 
C) 5.629, 26.12 
D) 7.261, 25.00 Using d.f. = n - 1 = 15, we get χ2L = 6.262 and χ2U = 27.49 from AppendixE. 
A) 6.262, 27.49 
B) 6.908, 28.85 
C) 5.629, 26.12 
D) 7.261, 25.00 Using d.f. = n - 1 = 15, we get χ2L = 6.262 and χ2U = 27.49 from AppendixE.

Question 4

As the sample size increases, the standard error of the mean:

Accepted Answer

A) increases. 
B) decreases. 
C) may increase or decrease. 
A) increases. 
B) decreases. 
C) may increase or decrease.

Question 5

A financial institution wishes to estimate the mean balances owed by its credit card customers. The population standard deviation is $300. If a 99 percent confidence interval is used and an interval of ± $75 is desired, how many cardholders should be sampled?

Accepted Answer

A) 3382 
B) 629 
C) 87 
D) 107 
A) 3382 
B) 629 
C) 87 
D) 107

Question 6

The confidence level refers to the procedure used to construct the confidence interval, rather than to the particular confidence interval we have constructed.

Accepted Answer

A) True 
 B)False

If a normal population has parameters μ = 40 and σ = 8, then for a sample size n = 4:

A company wants to estimate the time its trucks take to drive from city A to cityB. The standard deviation is known to be 12 minutes. What sample size is required in order that the error will not exceed ±2 minutes, with 95 percent confidence?

For a sample of size 16, the critical values of chi-square for a 95 percent confidence interval for the population variance are:

As the sample size increases, the standard error of the mean:

A financial institution wishes to estimate the mean balances owed by its credit card customers. The population standard deviation is $300. If a 99 percent confidence interval is used and an interval of ± $75 is desired, how many cardholders should be sampled?

The confidence level refers to the procedure used to construct the confidence interval, rather than to the particular confidence interval we have constructed.

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Continuous Probability Distributions

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Time Series Analysis

Chi-Square Tests

Nonparametric Tests

Quality Management

Filters

Exam 8: Sampling Distributions and Estimation

If a normal population has parameters μ = 40 and σ = 8, then for a sample size n = 4:

A company wants to estimate the time its trucks take to drive from city A to cityB. The standard deviation is known to be 12 minutes. What sample size is required in order that the error will not exceed ±2 minutes, with 95 percent confidence?

For a sample of size 16, the critical values of chi-square for a 95 percent confidence interval for the population variance are:

As the sample size increases, the standard error of the mean:

A financial institution wishes to estimate the mean balances owed by its credit card customers. The population standard deviation is $300. If a 99 percent confidence interval is used and an interval of ± $75 is desired, how many cardholders should be sampled?

The confidence level refers to the procedure used to construct the confidence interval, rather than to the particular confidence interval we have constructed.

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Continuous Probability Distributions

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Time Series Analysis

Chi-Square Tests

Nonparametric Tests

Quality Management

Filters