Question 1

In testing the hypothesis  , the following information is known: n = 64,  = 78, and  = 10. The test statistic is equal to:

Accepted Answer

A)  +1.96 
B)  +2.4 
C)  -2.4 
D)  -1.96 
E)  +2.58

Question 2

If you wish to determine there is evidence that average starting salary for finance graduates exceeds $42,000, then you should formulate the null and alternative hypotheses such that:

Accepted Answer

A)  either a two-tailed or one-tailed test could be used 
B)  a two-tailed test should be used 
C)  a one-tailed test should be used 
D)  the probability of committing a Type II error is equal to 0.42 
E)  a two-tailed test should be used and the probability of committing a Type II error is equal to 0.42

Question 3

If the p-value for a hypothesis test is less than a preassigned significance level  , then the null hypothesis can be rejected, and you can report that the results are statistically significant at level  .

Accepted Answer

A) True 
 B)False

Question 4

Suppose in testing a hypothesis about a proportion, the p-value is computed to be 0.027. The null hypothesis should be rejected if the chosen level of significance is 0.01.

Accepted Answer

A) True 
 B)False

Question 5

In a one-tail test for the population proportion, if the null hypothesis is not rejected when the alternative hypothesis is false, a Type II error is committed.

Accepted Answer

A) True 
 B)False

Question 6

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 7

The expected value of  is E (  ) =  .

Accepted Answer

A) True 
 B)False

Question 8

Develop the null and appropriate hypotheses that are most appropriate for each of the following situations: A meteorologist claims that the average high temperature for the month of August in Chicago, Illinois is 83°F. If the residents of Chicago do not believe this to be true, what hypotheses should they test? H₀: ______________ H₁: ______________ A car manufacturing plant is acting in accordance with the public's interest in making cars that have gas mileage of at least 28 miles per gallon. The supervisor will only let the cars off the manufacturing floor if the gas mileage is more than 25 miles per gallon. What hypotheses should the plant test? H₀: ______________ H₁: ______________ A spokesperson for the Health Department reports that a fish is unsafe for human consumption if the polychlorinated biphenyl (PCB) concentration exceeds 5 ppb. The Carlson family is interested in the mean PCB concentration in a fish from the lake on which they live. What hypotheses should they test? H₀: ______________ H₁: ______________ An Internet survey revealed that 50% of Internet users received more than 10 e-mail messages per day. A similar study on the use of e-mail was repeated. The purpose of the study was to see whether use of e-mail has increased. H₀: ______________ H₁: ______________

Accepted Answer

The answer of Develop the null and appropriate hypotheses that...

Question 9

The p-value in hypothesis testing equals the probability, 1 -  , of avoiding the Type I error of erroneously rejecting a null hypothesis that is in fact true.

Accepted Answer

A) True 
 B)False

Question 10

A professor of statistics refutes the claim that the proportion of Republican voters in Michigan is at most 44%. To test the claim, the hypotheses:  ,  , should be used.

Accepted Answer

A) True 
 B)False

Question 11

In testing the difference between two population means using two independent samples, the sampling distribution of the sample mean difference  is normal if:

Accepted Answer

A)  the sample sizes are both greater than 30 
B)  the populations are normal 
C)  the populations are non-normal and the sample sizes are large 
D)  all of these 
E)  none of these

Question 12

In testing  vs.  , which of the following statements is true as a result of increasing the sample size?

Accepted Answer

A)  The sampling distribution of the sample meanhas less variability. 
B)  There is no effect on the level of significance for the test. 
C)  There is no effect on whether the null hypothesis is true or false. 
D)  All of these. 
E)  None of these.

Question 13

If the null hypothesis, H0, cannot be corroborated in a hypothesis test,  is tentatively embraced, which calls for action; thus, one can think of  as the action hypothesis.

Accepted Answer

A) True 
 B)False

Question 14

A Type II error for a statistical test is committed if we do not reject the null hypothesis when it is false.

Accepted Answer

A) True 
 B)False

Question 15

In large-sample statistical tests about the population mean  , instead of using  directly as the test statistic, it is common practice to use:

Accepted Answer

A)  , if σ is known 
B)  , if s is known 
C)  , if β is known 
D)  both  , if σ is known and , if s is known 
E)  neither , if σ is known , if s is known

Question 16

Which of the following would be an appropriate null hypothesis?

Accepted Answer

A)  The population proportion is equal to 0.60. 
B)  The sample proportion is equal to 0.60. 
C)  The population proportion is not equal to 0.60. 
D)  The population proportion is greater than 0.60. 
E)  All of these.

Question 17

A professor claims that 70% of College of Business graduates earn more than $45,000 per year. In a random sample of 300 graduates, 195 earn more than $45,000. Can we reject the professor's claim at the 5% significance level?
Test statistic = ______________
p-value = ______________
Conclusion: ______________
Interpretation: __________________________________________

Accepted Answer

The answer of A professor claims that 70% of College...

Question 18

In a hypothesis test, if the null hypothesis has been rejected, then it is impossible that a Type II error has been committed.

Accepted Answer

A) True 
 B)False

Question 19

When the necessary conditions are met, a two-tailed test is being conducted for the difference between two population proportions. If the value of the test statistic is 1.96, then the null hypothesis is rejected at  = 0.10.

Accepted Answer

A) True 
 B)False

Question 20

For a given data set and confidence level, the confidence interval of the population proportion p will be wider for 95% confidence than for 90% confidence.

Accepted Answer

A) True 
 B)False

Exam 9: Large-Sample Tests of Hypotheses

In testing the hypothesis , the following information is known: n = 64, = 78, and = 10. The test statistic is equal to:

If you wish to determine there is evidence that average starting salary for finance graduates exceeds $42,000, then you should formulate the null and alternative hypotheses such that:

If the p-value for a hypothesis test is less than a preassigned significance level , then the null hypothesis can be rejected, and you can report that the results are statistically significant at level .

Suppose in testing a hypothesis about a proportion, the p-value is computed to be 0.027. The null hypothesis should be rejected if the chosen level of significance is 0.01.

In a one-tail test for the population proportion, if the null hypothesis is not rejected when the alternative hypothesis is false, a Type II error is committed.

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.

The expected value of is E ( ) = .

The p-value in hypothesis testing equals the probability, 1 - , of avoiding the Type I error of erroneously rejecting a null hypothesis that is in fact true.

A professor of statistics refutes the claim that the proportion of Republican voters in Michigan is at most 44%. To test the claim, the hypotheses: , , should be used.

In testing the difference between two population means using two independent samples, the sampling distribution of the sample mean difference is normal if:

In testing vs. , which of the following statements is true as a result of increasing the sample size?

If the null hypothesis, H₀, cannot be corroborated in a hypothesis test, is tentatively embraced, which calls for action; thus, one can think of as the action hypothesis.

A Type II error for a statistical test is committed if we do not reject the null hypothesis when it is false.

In large-sample statistical tests about the population mean , instead of using directly as the test statistic, it is common practice to use:

Which of the following would be an appropriate null hypothesis?

In a hypothesis test, if the null hypothesis has been rejected, then it is impossible that a Type II error has been committed.

When the necessary conditions are met, a two-tailed test is being conducted for the difference between two population proportions. If the value of the test statistic is 1.96, then the null hypothesis is rejected at = 0.10.

For a given data set and confidence level, the confidence interval of the population proportion p will be wider for 95% confidence than for 90% confidence.