Question 1

Exhibit 11-6
   We want to test the hypothesis that the population variances are equal.
-Refer to Exhibit 11-6.The p-value is between

Accepted Answer

A) 0.025 and 0.05 
B) 0.05 and 0.10 
C) 0.10 and 0.20 
D) 0.00 and 0.01 
A) 0.025 and 0.05 
B) 0.05 and 0.10 
C) 0.10 and 0.20 
D) 0.00 and 0.01 B

Question 2

Which of the following has a chi-square distribution?

Accepted Answer

A) (n - 1) $\sigma$2/S2 
B) (n - 2) $\sigma$2/S2 
C) (n - 1)S/ $\sigma$ 
D) (n - 1)S2/ $\sigma$2 
A) (n - 1) $\sigma$2/S2 
B) (n - 2) $\sigma$2/S2 
C) (n - 1)S/ $\sigma$ 
D) (n - 1)S2/ $\sigma$2 D

Question 3

The symbol used for the variance of the sample is

Accepted Answer

A)  $\sigma$ 
B)  $\sigma$2 
C) S 
D) S2 
A)  $\sigma$ 
B)  $\sigma$2 
C) S 
D) S2 D

Question 4

The 99% confidence interval estimate for a population variance when a sample standard deviation of 12 is obtained from a sample of 10 items is

Accepted Answer

A) 4.58 to 62.25 
B) 46.53 to 422.17 
C) 54.94 to 747.01 
D) 62.04 to 562.89 
A) 4.58 to 62.25 
B) 46.53 to 422.17 
C) 54.94 to 747.01 
D) 62.04 to 562.89

Question 5

Exhibit 11-4
  
-Refer to Exhibit 11-4.The p-value is between

Accepted Answer

A) 0.025 and 0.05 
B) 0.05 and 0.1 
C) 0.1 and 0.2 
D) 0.2 and 0.3 
A) 0.025 and 0.05 
B) 0.05 and 0.1 
C) 0.1 and 0.2 
D) 0.2 and 0.3

Question 6

A large company has claimed that the standard deviation of the monthly incomes of their employees is less than or equal to $120.To test their claim,a random sample of 76 employees of the company was taken;and it was determined that the standard deviation of their incomes was $135.At 90% confidence,test the company's claim.

Accepted Answer

@#IMG-DLM& chi-square = 94.92

Question 7

A sample of 61 observations yielded a sample standard deviation of 6.If we want to test
Ho:  $\sigma$2 = 40,the test statistic is

Accepted Answer

A) 54 
B) 9.15 
C) 54.90 
D) 9 
A) 54 
B) 9.15 
C) 54.90 
D) 9

Question 8

A sample of 20 cans of tomato juice showed a standard deviation of 0.4 ounces.A 95% confidence interval estimate of the variance for the population is

Accepted Answer

A) 0.2313 to 0.8533 
B) 0.2224 to 0.7924 
C) 0.3042 to 0.5843 
D) 0.0925 to 0.3413 
A) 0.2313 to 0.8533 
B) 0.2224 to 0.7924 
C) 0.3042 to 0.5843 
D) 0.0925 to 0.3413

Question 9

A random sample of 20 observations showed a standard deviation of 8.At 95% confidence,test to see if the variance of the population is significantly less than 65.Use the critical value approach.

Accepted Answer

H₀: @#LAT-DLM&² @#LAT-DLM&

Question 10

The 90% confidence interval estimate for a population standard deviation when a sample variance of 50 is obtained from a sample of 15 items is

Accepted Answer

A) 4.18 to 15.07 
B) 5.18 to 11.15 
C) 5.44 to 10.32 
D) 29.55 to 106.53 
A) 4.18 to 15.07 
B) 5.18 to 11.15 
C) 5.44 to 10.32 
D) 29.55 to 106.53

Question 11

A sample of n observations is taken from a population.The appropriate chi-square distribution has

Accepted Answer

A) n degrees of freedom 
B) n - 1 degrees of freedom 
C) n - 2 degrees of freedom 
D) n - 3 degrees of freedom 
A) n degrees of freedom 
B) n - 1 degrees of freedom 
C) n - 2 degrees of freedom 
D) n - 3 degrees of freedom

Question 12

At $\alpha$ = 0.1,test to see if the population variances from which the following samples were drawn are equal.

Accepted Answer

Since F = 1.26 < 2.1

Question 13

Exhibit 11-5
  
-Refer to Exhibit 11-5.The test statistic for this problem equals

Accepted Answer

A) .63 
B) 12.68 
C) 13.33 
D) 13.66 
A) .63 
B) 12.68 
C) 13.33 
D) 13.66

Question 14

Exhibit 11-6
   We want to test the hypothesis that the population variances are equal.
-Refer to Exhibit 11-6.The test statistic for this problem equals

Accepted Answer

A) 0.417 
B) .843 
C) 2.4 
D) 1.500 
A) 0.417 
B) .843 
C) 2.4 
D) 1.500

Question 15

The average grade of a sample of 30 students on their second statistics examination was 85 with a standard deviation of 11.Is the variance of the population significantly more than 80? Use a 0.05 level of significance.

Accepted Answer

The answer of The average grade of a sample of...

Question 16

Exhibit 11-7
   We want to test the hypothesis that population A has a larger variance than population B.
-Refer to Exhibit 11-7.The test statistic for this problem equals

Accepted Answer

A) 0.4132 
B) 1.96 
C) 2.42 
D) 1.645 
A) 0.4132 
B) 1.96 
C) 2.42 
D) 1.645

Question 17

Exhibit 11-1
Last year,the standard deviation of the ages of the students at UA was 1.8 years.Recently,a sample of 61 students had a standard deviation of 2.1 years.We are interested in testing to see if there has been a significant change in the standard deviation of the ages of the students at UA.
-Refer to Exhibit 11-1.At 95% confidence the null hypothesis

Accepted Answer

A) should be rejected 
B) should not be rejected 
C) should be revised 
D) None of these alternatives is correct. 
A) should be rejected 
B) should not be rejected 
C) should be revised 
D) None of these alternatives is correct.

Question 18

The sampling distribution of the ratio of two independent sample variances taken from normal populations with equal variances is

Accepted Answer

A) an F distribution 
B) a chi-square distribution 
C) a t distribution 
D) a normal distribution 
A) an F distribution 
B) a chi-square distribution 
C) a t distribution 
D) a normal distribution

Question 19

It has been suggested that night shift-workers show more variability in their output levels than day workers.Below,you are given the results of two independent random samples.
   
a.State the null and alternative hypotheses to be tested.
b.Compute the test statistic.
c.Determine the p-value.
d.At 95% confidence,what do you conclude?

Accepted Answer

a.H₀: @#LAT-DLM&²₁

Question 20

An egg packing company has stated that the standard deviation of the weights of their grade A large eggs is 0.07 ounces or less.The sample variance for 51 eggs was 0.0065 ounces.Can this sample result confirm the company's claim?
Use $\alpha$= 0.1.

Accepted Answer

The answer of An egg packing company has stated that...

Exhibit 11-6 We want to test the hypothesis that the population variances are equal. -Refer to Exhibit 11-6.The p-value is between

Which of the following has a chi-square distribution?

The symbol used for the variance of the sample is

The 99% confidence interval estimate for a population variance when a sample standard deviation of 12 is obtained from a sample of 10 items is

Exhibit 11-4 -Refer to Exhibit 11-4.The p-value is between

A sample of 61 observations yielded a sample standard deviation of 6.If we want to test H_o: $\sigma$ ² = 40,the test statistic is

A sample of 20 cans of tomato juice showed a standard deviation of 0.4 ounces.A 95% confidence interval estimate of the variance for the population is

A random sample of 20 observations showed a standard deviation of 8.At 95% confidence,test to see if the variance of the population is significantly less than 65.Use the critical value approach.

The 90% confidence interval estimate for a population standard deviation when a sample variance of 50 is obtained from a sample of 15 items is

A sample of n observations is taken from a population.The appropriate chi-square distribution has

At $\alpha$ = 0.1,test to see if the population variances from which the following samples were drawn are equal. $At \alpha = 0.1,test to see if the population variances from which the following samples were drawn are equal.$

Exhibit 11-5 -Refer to Exhibit 11-5.The test statistic for this problem equals

Exhibit 11-6 We want to test the hypothesis that the population variances are equal. -Refer to Exhibit 11-6.The test statistic for this problem equals

The average grade of a sample of 30 students on their second statistics examination was 85 with a standard deviation of 11.Is the variance of the population significantly more than 80? Use a 0.05 level of significance.

Exhibit 11-7 We want to test the hypothesis that population A has a larger variance than population B. -Refer to Exhibit 11-7.The test statistic for this problem equals

The sampling distribution of the ratio of two independent sample variances taken from normal populations with equal variances is

An egg packing company has stated that the standard deviation of the weights of their grade A large eggs is 0.07 ounces or less.The sample variance for 51 eggs was 0.0065 ounces.Can this sample result confirm the company's claim? Use $\alpha$ = 0.1.

Data and Statistics

Descriptive Statistics: Tabular and Graphical Presentations

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Hypothesis Tests

Statistical Inference About Means and Proportions With Two Populations

Tests of Goodness of Fit and Independence

Analysis of Variance and Experimental Design

Simple Linear Regression

Multiple Regression

Regression Analysis: Model Building

Index Numbers

Forecasting

Nonparametric Methods

Statistical Methods for Quality Control

Decision Analysis

Sample Survey

Filters

Exam 11: Inferences About Population Variances

Exhibit 11-6 We want to test the hypothesis that the population variances are equal. -Refer to Exhibit 11-6.The p-value is between

Which of the following has a chi-square distribution?

The symbol used for the variance of the sample is

The 99% confidence interval estimate for a population variance when a sample standard deviation of 12 is obtained from a sample of 10 items is

Exhibit 11-4 -Refer to Exhibit 11-4.The p-value is between

A sample of 61 observations yielded a sample standard deviation of 6.If we want to test Ho: σ\sigmaσ 2 = 40,the test statistic is

A sample of 20 cans of tomato juice showed a standard deviation of 0.4 ounces.A 95% confidence interval estimate of the variance for the population is

A random sample of 20 observations showed a standard deviation of 8.At 95% confidence,test to see if the variance of the population is significantly less than 65.Use the critical value approach.

The 90% confidence interval estimate for a population standard deviation when a sample variance of 50 is obtained from a sample of 15 items is

A sample of n observations is taken from a population.The appropriate chi-square distribution has

At α\alphaα = 0.1,test to see if the population variances from which the following samples were drawn are equal.

Exhibit 11-5 -Refer to Exhibit 11-5.The test statistic for this problem equals

Exhibit 11-6 We want to test the hypothesis that the population variances are equal. -Refer to Exhibit 11-6.The test statistic for this problem equals

The average grade of a sample of 30 students on their second statistics examination was 85 with a standard deviation of 11.Is the variance of the population significantly more than 80? Use a 0.05 level of significance.

Exhibit 11-7 We want to test the hypothesis that population A has a larger variance than population B. -Refer to Exhibit 11-7.The test statistic for this problem equals

The sampling distribution of the ratio of two independent sample variances taken from normal populations with equal variances is

An egg packing company has stated that the standard deviation of the weights of their grade A large eggs is 0.07 ounces or less.The sample variance for 51 eggs was 0.0065 ounces.Can this sample result confirm the company's claim? Use α\alphaα = 0.1.

Data and Statistics

Descriptive Statistics: Tabular and Graphical Presentations

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Hypothesis Tests

Statistical Inference About Means and Proportions With Two Populations

Tests of Goodness of Fit and Independence

Analysis of Variance and Experimental Design

Simple Linear Regression

Multiple Regression

Regression Analysis: Model Building

Index Numbers

Forecasting

Nonparametric Methods

Statistical Methods for Quality Control

Decision Analysis

Sample Survey

Filters

A sample of 61 observations yielded a sample standard deviation of 6.If we want to test H_o: $\sigma$ ² = 40,the test statistic is

At $\alpha$ = 0.1,test to see if the population variances from which the following samples were drawn are equal. $At \alpha = 0.1,test to see if the population variances from which the following samples were drawn are equal.$

An egg packing company has stated that the standard deviation of the weights of their grade A large eggs is 0.07 ounces or less.The sample variance for 51 eggs was 0.0065 ounces.Can this sample result confirm the company's claim? Use $\alpha$ = 0.1.