Question 1

Which of the following distributions is used in testing   vs.

Accepted Answer

A)  Chi-square distribution 
B)  Normal distribution 
C)  F-distribution 
D)  t-distribution 
E)  Chi-square distribution and Normal distribution 
A)  Chi-square distribution 
B)  Normal distribution 
C)  F-distribution 
D)  t-distribution 
E)  Chi-square distribution and Normal distribution

Question 2

If a hypothesis test is to be conducted regarding a population variance, then the critical value of the test will be obtained using the:

Accepted Answer

A)  normal distribution 
B)  t-distribution with n - 1 degrees of freedom 
C)  chi-square distribution with n - 1 degrees of freedom 
D)  binomial distribution 
E)  t-distribution with n + 1 degrees of freedom 
A)  normal distribution 
B)  t-distribution with n - 1 degrees of freedom 
C)  chi-square distribution with n - 1 degrees of freedom 
D)  binomial distribution 
E)  t-distribution with n + 1 degrees of freedom

Question 3

A test is being conducted to test the difference between two population means using data that are gathered from a matched pairs experiment. If the paired differences are normal, then the distribution used for testing is the:

Accepted Answer

A)  normal distribution 
B)  binomial distribution 
C)  Student t-distribution 
D)  F distribution 
E)  paired distribution 
A)  normal distribution 
B)  binomial distribution 
C)  Student t-distribution 
D)  F distribution 
E)  paired distribution

Question 4

Suppose that a t-test is being conducted at the 0.05 level of significance to test   vs.   . A sample of size 20 is randomly selected. The rejection region is:

Accepted Answer

A)  t > 1.725 
B)  t  -2.093 
D)  t  1.935 
A)  t > 1.725 
B)  t  -2.093 
D)  t  1.935

Question 5

Two independent samples are selected at random from two normal populations. The sample statistics are as follows:           and   Assume that a two-tailed hypothesis test is conducted at   , what is the value of the test statistic?

Accepted Answer

A)  z = 1.645 
B)  t = 0.891 
C)  z = 1.960 
D)  t = 0.928 
E)  t = 0.945 
A)  z = 1.645 
B)  t = 0.891 
C)  z = 1.960 
D)  t = 0.928 
E)  t = 0.945

Question 6

If a sample has 18 observations and a 90% confidence estimate for   is needed, the appropriate t-score is 1.740.

Accepted Answer

A) True 
 B)False

Question 7

A political analyst in Iowa surveys a random sample of registered Democrats and compares the results with those obtained from a random sample of registered Republicans. This would be an example of two independent samples.

Accepted Answer

A) True 
 B)False

Question 8

In a one-tailed test of the equality of two population variances, the F-test statistic is calculated by placing the larger sample variance in the numerator.

Accepted Answer

A) True 
 B)False

Question 9

The t-distribution approaches the normal distribution as the number of degrees of freedom increases.

Accepted Answer

A) True 
 B)False

Question 10

The variance of   is equal to   .

Accepted Answer

A) True 
 B)False

Question 11

The number of degrees of freedom associated with the t-test, when the data are gathered from a matched pairs experiment with 8 pairs, is 7.

Accepted Answer

A) True 
 B)False

Question 12

A random sample of size 10 produced a sample mean equal to 12 and a standard deviation equal to .15. Based on this information, the upper limit for a 95% confidence interval estimate is approximately 12.107.

Accepted Answer

A) True 
 B)False

Question 13

One reason for performing a paired-difference experiment is to:

Accepted Answer

A)  reduce the degrees of freedom 
B)  allow one to use a larger value of 
C)  reduce the quantity of information in the experiment 
D)  reduce the variability in the sample data 
E)  do none of these 
A)  reduce the degrees of freedom 
B)  allow one to use a larger value of 
C)  reduce the quantity of information in the experiment 
D)  reduce the variability in the sample data 
E)  do none of these

Question 14

A scientist is testing two different types of Secchi discs. This is an instrument used for determining water clarity. The scientist takes a depth reading (in feet below the surface) with each disc at 8 different locations on a lake. The results of the 8 different locations for each Secchi disc are listed below.   Assume the two population distributions are normal. Determine if there is a significant difference in average depth reading for the two discs. Use a significance level of   = 0.01.
Use the Data Analysis software if you prefer.
Test Statistic = ______________
Reject Region: Reject H0 if |t| > ______________
Conclusion: ______________
The sample evidence supports that the two discs ______________.

Accepted Answer

1.9299; 3.499; Do no

Question 15

A logger knows the average time for his cutting machine to cut 20 trees is 9.8 minutes. A new machine on the market claims to cut the trees in less than 9.8 minutes. A random sample of 25 test runs on the new machine yielded a mean of 8.5 minutes with a standard deviation of 1.5. Does the sample data suggest the new machine cuts faster than the logger's machine? Test at the   = 0.05 level. Assume the cutting time is normally distributed and interpret your results.
Test Statistic = ______________
____________________________
The new machine ______________ cut faster than the logger's machine.

Accepted Answer

-4.33; Rej

Question 16

A car salesperson tries to convince customers buying a new Honda Accord that the gas mileage varies by only   2 miles per gallon when driving in town and on the highway. The customer found, for 14 randomly chosen tanks of gas, the gas mileage to vary by   2.8 miles per gallon. Do the customer's results contradict the salesperson's claim? Test the relevant hypotheses at the 0.05 level of significance. Assume the sample comes from a normal population.
Test Statistic = ______________
Reject Region: Reject H0 if   > ______________
Conclusion: ______________
Interpretation: ________________________________________________________

Accepted Answer

25.48; 24.7356; Reje

Question 17

In testing the difference between two population means using two independent samples, the population standard deviations are assumed to be known, and the calculated test statistic equals 2.75. If the test is two-tail and 5% level of significance has been specified, the conclusion should not be reject the null hypothesis.

Accepted Answer

A) True 
 B)False

Question 18

The t-test for the difference between the means of two independent populations assumes that the respective:

Accepted Answer

A)  sample sizes are equal 
B)  sample variances are equal 
C)  populations are approximately normal 
D)  all of these 
E)  none of these 
A)  sample sizes are equal 
B)  sample variances are equal 
C)  populations are approximately normal 
D)  all of these 
E)  none of these

Question 19

The chi-squared distribution is:

Accepted Answer

A)  symmetrical about 0 
B)  positively skewed ranging between 0 and 
C)  symmetrical around 
D)  negatively skewed ranging between -and 0 
E)  mound-shaped 
A)  symmetrical about 0 
B)  positively skewed ranging between 0 and 
C)  symmetrical around 
D)  negatively skewed ranging between -and 0 
E)  mound-shaped

Question 20

The sampling distribution of the quantity   is:

Accepted Answer

A)  an F distribution 
B)  a chi-square distribution 
C)  a normal distribution 
D)  a t-distribution 
E)  none of these 
A)  an F distribution 
B)  a chi-square distribution 
C)  a normal distribution 
D)  a t-distribution 
E)  none of these

Which of the following distributions is used in testing vs.

If a hypothesis test is to be conducted regarding a population variance, then the critical value of the test will be obtained using the:

A test is being conducted to test the difference between two population means using data that are gathered from a matched pairs experiment. If the paired differences are normal, then the distribution used for testing is the:

Suppose that a t-test is being conducted at the 0.05 level of significance to test vs. . A sample of size 20 is randomly selected. The rejection region is:

Two independent samples are selected at random from two normal populations. The sample statistics are as follows: and Assume that a two-tailed hypothesis test is conducted at , what is the value of the test statistic?

If a sample has 18 observations and a 90% confidence estimate for is needed, the appropriate t-score is 1.740.

A political analyst in Iowa surveys a random sample of registered Democrats and compares the results with those obtained from a random sample of registered Republicans. This would be an example of two independent samples.

In a one-tailed test of the equality of two population variances, the F-test statistic is calculated by placing the larger sample variance in the numerator.

The t-distribution approaches the normal distribution as the number of degrees of freedom increases.

The variance of is equal to .

The number of degrees of freedom associated with the t-test, when the data are gathered from a matched pairs experiment with 8 pairs, is 7.

A random sample of size 10 produced a sample mean equal to 12 and a standard deviation equal to .15. Based on this information, the upper limit for a 95% confidence interval estimate is approximately 12.107.

One reason for performing a paired-difference experiment is to:

The t-test for the difference between the means of two independent populations assumes that the respective:

The chi-squared distribution is:

The sampling distribution of the quantity is:

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 Estimation

Large-Sample Tests of Hypotheses

The Analysis of Variance

Linear Regression and Correlation

Multiple Regression Analysis

Analysis of Categorical Data

Nonparametric Statistics

Filters

Exam 10: Inference From Small Samples

Which of the following distributions is used in testing vs.

If a hypothesis test is to be conducted regarding a population variance, then the critical value of the test will be obtained using the:

A test is being conducted to test the difference between two population means using data that are gathered from a matched pairs experiment. If the paired differences are normal, then the distribution used for testing is the:

Suppose that a t-test is being conducted at the 0.05 level of significance to test vs. . A sample of size 20 is randomly selected. The rejection region is:

Two independent samples are selected at random from two normal populations. The sample statistics are as follows: and Assume that a two-tailed hypothesis test is conducted at , what is the value of the test statistic?

If a sample has 18 observations and a 90% confidence estimate for is needed, the appropriate t-score is 1.740.

A political analyst in Iowa surveys a random sample of registered Democrats and compares the results with those obtained from a random sample of registered Republicans. This would be an example of two independent samples.

In a one-tailed test of the equality of two population variances, the F-test statistic is calculated by placing the larger sample variance in the numerator.

The t-distribution approaches the normal distribution as the number of degrees of freedom increases.

The variance of is equal to .

The number of degrees of freedom associated with the t-test, when the data are gathered from a matched pairs experiment with 8 pairs, is 7.

A random sample of size 10 produced a sample mean equal to 12 and a standard deviation equal to .15. Based on this information, the upper limit for a 95% confidence interval estimate is approximately 12.107.

One reason for performing a paired-difference experiment is to:

The t-test for the difference between the means of two independent populations assumes that the respective:

The chi-squared distribution is:

The sampling distribution of the quantity is:

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 Estimation

Large-Sample Tests of Hypotheses

The Analysis of Variance

Linear Regression and Correlation

Multiple Regression Analysis

Analysis of Categorical Data

Nonparametric Statistics

Filters