Stats 2 Mid Term (combined tests)

Exhibit 10-12 The results of a recent poll on the preference of teenagers regarding the types of music they listen to are shown below. Music Type Teenagers Surveyed Teenagers Favoring This Type Pop 800 384 Rap 900 450 Refer to Exhibit 10-12. The point estimate for the difference between the proportions is _____. a. 100 b. -.02 c. 66 d. .048

-.02

Exhibit 10-12 The results of a recent poll on the preference of teenagers regarding the types of music they listen to are shown below. Music Type Teenagers Surveyed Teenagers Favoring This Type Pop 800 384 Rap 900 450 Refer to Exhibit 10-12. The 95% confidence interval for the difference between the two proportions is _____. a. .028 to .068 b. 384 to 450 c. .48 to .5 d. -.068 to .028

-.068 to .028

Exhibit 10-5 The following information was obtained from matched samples. Individual Method 1 Method 2 1 7 5 2 5 9 3 6 8 4 7 7 5 5 6 Refer to Exhibit 10-5. The point estimate for the mean of the population of differences is _____. a. 1 b. 2 c. 0 d. -1

-1

Read the t statistic from the table of t distributions and circle the correct answer. A one-tailed test (lower tail), a sample size of 10 at a .10 level of significance; t = _____. a. 1.383 b. -2.821 c. -1.372 d. -1.383

-1.383

Read the z statistic from the normal distribution table and circle the correct answer. A one-tailed test (lower tail) at a .063 level of significance; z = _____. a. -1.86 b. -1.645 c. -1.96 d. -1.53

-1.53

Exhibit 9-5 n = 16 H0: μ ≥ 80 x̄ = 75.607 Ha: μ < 80 σ = 8.246 Assume the population is normally distributed. The test statistic equals _____. a. 2.131 b. -2.131 c. .53 d. -.53

-2.131

In testing the null hypothesis H0: μ1 - μ2 = 0, the computed test statistic is z = -1.66. The corresponding p-value is _____. a. .9515 b. .9030 c. .0970 d. .0485

.0970

In hypothesis testing, the hypothesis tentatively assumed to be true is _____. a. either the null or the alternative b. the null hypothesis c. the alternative hypothesis d. None of these answers are correct.

the null hypothesis

Exhibit 10-3 A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago. Final examination scores from a random sample of students enrolled today and from a random sample of students enrolled five years ago were selected. You are given the following information. Today Five Years Ago x̄ 82 88 σ 2 112.5 54 n 45 36 Refer to Exhibit 10-3. The test statistic for the difference between the two population means is _____. a. -.47 b. -3 c. -1.5 d. -.65

-3

Exhibit 10-5 The following information was obtained from matched samples. Individual Method 1 Method 2 1 7 5 2 5 9 3 6 8 4 7 7 5 5 6 Refer to Exhibit 10-5. The 95% confidence interval for the mean of the population of differences is _____. a. -3.776 to 1.776 b. -2.776 to 2.776 c. -1.776 to 2.776 d. 0 to 3.776

-3.776 to 1.776

Excel's __________ function can be used to calculate a p-value for a hypothesis test. a. NORM.S.DIST b. NORM.S.INV c. RAND d. Not enough information is given to answer this question.

. NORM.S.DIST

Exhibit 10-11 An insurance company selected samples of clients under 18 years of age and over 18 and recorded the number of accidents they had in the previous year. The results are shown below. Under Age 18 Over Age 18 n1 = 500 n2 = 600 Number of accidents = 180 Number of accidents = 150 We are interested in determining if the accident proportions differ between the two age groups. Refer to Exhibit 10-11 and let pu represent the proportion under and po the proportion over the age of 18. The null hypothesis is _____. a. pu - po ≠ 0 b. pu - po ≥ 0 c. pu - po ≤ 0 d. pu - po = 0

. pu - po = 0

Exhibit 9-1 n = 36 H0: μ ≤ 20 x̄ = 24.6 Ha: μ > 20 σ = 12 The p-value is _____. a. .0214 b. 2.1 c. .5107 d. .0107

.0107

Exhibit 10-10 The results of a recent poll on the preference of shoppers regarding two products are shown below. Product Shoppers Surveyed Shoppers Favoring This Product A 800 560 B 900 612 Refer to Exhibit 10-10. The point estimate for the difference between the two population proportions in favor of this product (Product A - Product B) is _____. a. 52 b. .02 c. 100 d. .44

.02

Exhibit 10-10 The results of a recent poll on the preference of shoppers regarding two products are shown below. Product Shoppers Surveyed Shoppers Favoring This Product A 800 560 B 900 612 Refer to Exhibit 10-10. The standard error of p̄ 1 - p̄ 2 is _____. a. .0225 b. 100 c. 52 d. .044

.0225

For a two-tailed hypothesis test with a test statistic value of z = 2.05, the p-value is _____. a. .0202 b. .0101 c. .4899 d. .0404

.0404

Exhibit 10-1 Salary information regarding two independent random samples of male and female employees of a large company is shown below. Male Female Sample size 64 36 Sample mean salary (in $1000s) 44 41 Population variance 128 72 Refer to Exhibit 10-1. The p-value is _____. a. .0668 b. 1.96 c. 1.336 d. .0334

.0668

Exhibit 10-7 In order to estimate the difference between the average hourly wages of employees of two branches of a department store, two independent random samples were selected and the following statistics were calculated. Downtown Store North Mall Store Sample size 25 20 Sample mean $9 $8 Sample standard deviation $2 $1 Refer to Exhibit 10-7. A 95% interval estimate for the difference between the two population means is _____. a. .071 to 1.928 b. 1.078 to 2.922 c. 1.922 to 2.078 d. 1.09 to 4.078

.071 to 1.928

Exhibit 8-2 The manager of a grocery store has selected a random sample of 100 customers. The average length of time it took these 100 customers to check out was 3.0 minutes. It is known that the standard deviation of the checkout time is 1 minute. Refer to Exhibit 8-2. The standard error of the mean equals _____. a. .01 b. .1 c. 1 d. .001

.1

Exhibit 9-6 A random sample of 100 people was taken. Eighty of the people in the sample favored Candidate A. We are interested in determining whether or not the proportion of the population in favor of Candidate A is significantly more than 75%. The p-value is _____. a. .2112 b. .05 c. .1251 d. .025

.1251

Exhibit 8-1 In order to estimate the average time spent on the computer terminals per student at a local university, data were collected from a sample of 81 business students over a one-week period. Assume the population standard deviation is 1.2 hours. Refer to Exhibit 8-1. The standard error of the mean is _____. a. 7.5 b. .160 c. .133 d. .014

.133

Exhibit 9-3 n = 49 H0: μ = 50 x̄ = 54.8 Ha: μ ≠ 50 σ = 28 The p-value is equal to _____. a. .3849 b. .2698 c. .1151 d. .2302

.2302

Exhibit 10-11 An insurance company selected samples of clients under 18 years of age and over 18 and recorded the number of accidents they had in the previous year. The results are shown below. Under Age 18 Over Age 18 n1 = 500 n2 = 600 Number of accidents = 180 Number of accidents = 150 We are interested in determining if the accident proportions differ between the two age groups. Refer to Exhibit 10-11. The pooled proportion is _____. a. .305 b. .027 c. .300 d. .450

.300

If we want to provide a 95% confidence interval for the mean of a population, the confidence coefficient is _____. a. .95 b. 1.645 c. 1.96 d. .485

.95

Exhibit 10-2 The following information was obtained from matched samples. The daily production rates for a random sample of workers before and after a training program are shown below. Worker Before After 1 20 22 2 25 23 3 27 27 4 23 20 5 22 25 6 20 19 7 17 18 Refer to Exhibit 10-2. The point estimate for the mean of the population of difference is _____. a. 1 b. 0 c. -1 d. -2

0

The mean of the t distribution is _____. a. dependent upon the sample size b. .5 c. 0 d. 1

0

Exhibit 8-2 The manager of a grocery store has selected a random sample of 100 customers. The average length of time it took these 100 customers to check out was 3.0 minutes. It is known that the standard deviation of the checkout time is 1 minute. Refer to Exhibit 8-2. With a .95 probability, the sample mean will provide a margin of error of _____. a. .196 b. .95 c. 1.96 d. .10

0.196

Exhibit 10-7 In order to estimate the difference between the average hourly wages of employees of two branches of a department store, two independent random samples were selected and the following statistics were calculated. Downtown Store North Mall Store Sample size 25 20 Sample mean $9 $8 Sample standard deviation $2 $1 Refer to Exhibit 10-7. A point estimate for the difference between the two sample means (Downtown Store - North Mall Store) is _____. a. 2 b. 3 c. 4 d. 1

1

Exhibit 9-3 n = 49 H0: μ = 50 x̄ = 54.8 Ha: μ ≠ 50 σ = 28 The test statistic equals _____. a. .3849 b. 1.2 c. -1.2 d. .1714

1.2

Exhibit 10-1 Salary information regarding two independent random samples of male and female employees of a large company is shown below. Male Female Sample size 64 36 Sample mean salary (in $1000s) 44 41 Population variance 128 72 Refer to Exhibit 10-1. If you are interested in testing whether the average salary of males is significantly greater than that of females, the value of the test statistic is _____. a. 1.645 b. 1.96 c. 1.5 d. 2.0

1.5

Exhibit 8-3 A random sample of 81 automobiles traveling on a section of an interstate showed an average speed of 60 mph. The distribution of speeds of all cars on this section of highway is normally distributed, with a standard deviation of 13.5 mph. Refer to Exhibit 8-3. If we are interested in determining an interval estimate for μ at 86.9% confidence, the z value to use is _____. a. 1.96 b. 2.00 c. 1.51 d. 1.31

1.51

Read the t statistic from the table of t distributions and circle the correct answer. A one-tailed test (upper tail), a sample size of 18 at a .05 level of significance; t = _____. a. 1.734 b. 2.12 c. -1.740 d. 1.740

1.740

Exhibit 10-6 The management of a department store is interested in estimating the difference between the mean credit purchases of customers using the store's credit card versus those customers using a national major credit card. You are given the following information. Assume the samples were selected randomly. Store's Card Major Credit Card Sample size 64 49 Sample mean $140 $125 Population standard deviation $10 $8 Refer to Exhibit 10-6. A 95% confidence interval estimate for the difference (Store's Card - Major Credit Card) between the average purchases of the customers using the two different credit cards is _____. a. 49 to 64 b. 11.68 to 18.32 c. 8 to 10 d. 125 to 140

11.68 to 18.32

To estimate a population mean, the sample size needed to provide a margin of error of 2 or less with a .95 probability when the population standard deviation equals 11 is _____. a. 10 b. 116 c. 117 d. 11

117

Exhibit 10-6 The management of a department store is interested in estimating the difference between the mean credit purchases of customers using the store's credit card versus those customers using a national major credit card. You are given the following information. Assume the samples were selected randomly. Store's Card Major Credit Card Sample size 64 49 Sample mean $140 $125 Population standard deviation $10 $8 Refer to Exhibit 10-6. A point estimate for the difference between the mean purchases of the users of the two credit cards (Store's Card - Major Credit Card) is _____. a. 2 b. 265 c. 18 d. 15

15

Exhibit 10-3 A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago. Final examination scores from a random sample of students enrolled today and from a random sample of students enrolled five years ago were selected. You are given the following information. Today Five Years Ago x̄ 82 88 σ 2 112.5 54 n 45 36 Refer to Exhibit 10-3. The standard error of x̄ 1 - x̄ 2 is _____. a. 2 b. 4 c. 12.9 d. 9.3

2

Exhibit 10-1 Salary information regarding two independent random samples of male and female employees of a large company is shown below. Male Female Sample size 64 36 Sample mean salary (in $1000s) 44 41 Population variance 128 72 Refer to Exhibit 10-1. The standard error for the difference between the two means is _____. a. 4 b. 4.24 c. 7.46 d. 2.0

2.0

Exhibit 10-9 Two major automobile manufacturers have produced compact cars with the same size engines. We are interested in determining whether or not there is a significant difference in the MPG (miles per gallon) of the two brands of automobiles. A random sample of eight cars from each manufacturer is selected, and eight drivers are selected to drive each automobile for a specified distance. The following data show the results of the test. Driver Manufacturer A Manufacturer B 1 32 28 2 27 22 3 26 27 4 26 24 5 25 24 6 29 25 7 31 28 8 25 27 Refer to Exhibit 10-9. The mean of the differences (Manufacturer A - Manufacturer B) is _____. a. 1.5 b. 2.5 c. .50 d. 2.0

2.0

Exhibit 9-2 The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes. The population standard deviation is known to be 0.5 minute. We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes. The test statistic is _____. a. .056 b. 1.64 c. 2.00 d. 1.96

2.00

Exhibit 10-9 Two major automobile manufacturers have produced compact cars with the same size engines. We are interested in determining whether or not there is a significant difference in the MPG (miles per gallon) of the two brands of automobiles. A random sample of eight cars from each manufacturer is selected, and eight drivers are selected to drive each automobile for a specified distance. The following data show the results of the test. Driver Manufacturer A Manufacturer B 1 32 28 2 27 22 3 26 27 4 26 24 5 25 24 6 29 25 7 31 28 8 25 27 Refer to Exhibit 10-9. The value of the test statistic is _____. a. 2.096 b. 1.96 c. 2.256 d. 1.645

2.256

Exhibit 9-1 n = 36 H0: μ ≤ 20 x̄ = 24.6 Ha: μ > 20 σ = 12 The test statistic equals _____. a. -2.3 b. 2.3 c. -.38 d. .38

2.3

Exhibit 8-2 The manager of a grocery store has selected a random sample of 100 customers. The average length of time it took these 100 customers to check out was 3.0 minutes. It is known that the standard deviation of the checkout time is 1 minute. Refer to Exhibit 8-2. The 95% confidence interval for the average checkout time for all customers is _____. a. 1.04 to 4.96 b. 1.36 to 4.64 c. 2.804 to 3.196 d. 3 to 5

2.804 to 3.196

Exhibit 10-1 Salary information regarding two independent random samples of male and female employees of a large company is shown below. Male Female Sample size 64 36 Sample mean salary (in $1000s) 44 41 Population variance 128 72 Refer to Exhibit 10-1. The point estimate of the difference between the means of the two populations (Male - Female) is _____. a. 4 b. 3 c. -4 d. -28

3

Exhibit 10-8 In order to determine whether or not there is a significant difference between the hourly wages of two companies, two independent random samples were selected and the following statistics were calculated. Company A Company B Sample size 80 60 Sample mean $6.75 $6.25 Population standard deviation $1.00 $0.95 Refer to Exhibit 10-8. The value of the test statistic is _____. a. 1.645 b. 2.75 c. .098 d. 3.01

3.01

The use of the normal probability distribution as an approximation of the sampling distribution of p̄ is based on the condition that both np and n(1 - p) equal or exceed _____. a. .05 b. 5 c. 15 d. 30

5

Exhibit 8-3 A random sample of 81 automobiles traveling on a section of an interstate showed an average speed of 60 mph. The distribution of speeds of all cars on this section of highway is normally distributed, with a standard deviation of 13.5 mph. Refer to Exhibit 8-3. The 86.9% confidence interval for μ is _____. a. 57.735 to 62.265 b. 50 to 70 c. 59.131 to 60.869 d. 46.500 to 73.500

57.735 to 62.265

A random sample of 25 statistics examinations was selected. The average score in the sample was 76 with a variance of 144. Assuming the scores are normally distributed, the 99% confidence interval for the population average examination score is _____. a. 69.82 to 82.18 b. 70.02 to 81.98 c. 69.29 to 82.71 d. 70.06 to 81.94

69.29 to 82.71

A bank manager wishes to estimate the average waiting time for customers in line for tellers. A random sample of 50 times is measured and the average waiting time is 5.7 minutes. The population standard deviation of waiting time is 2 minutes. Which Excel function would be used to construct a confidence interval estimate? a. CONFIDENCE.NORM b. INT c. T.INV d. NORM.INV

CONFIDENCE.NORM

An auto manufacturer wants to estimate the annual income of owners of a particular model of automobile. A random sample of 200 current owners is selected. The population standard deviation is known. Which Excel function would NOT be appropriate to use to construct a confidence interval estimate? a. AVERAGE b. COUNTIF c. NORM.S.INV d. STDEV

COUNTIF

In the past, 75% of the tourists who visited Chattanooga went to see Rock City. The management of Rock City recently undertook an extensive promotional campaign. They are interested in determining whether the promotional campaign actually INCREASED the proportion of tourists visiting Rock City. The correct set of hypotheses is _____. a. H0: p ≥ .75 Ha: p < .75 b. H0: p < .75 Ha: p ≥ .75 c. H0: p ≤ .75 Ha: p > .75 d. H0: p > .75 Ha: p ≤ .75

H0: p ≤ .75 Ha: p > .75

Which of the following hypotheses is not a valid null hypothesis? a. H0: μ = 0 b. H0: μ ≤ 0 c. H0: μ ≥ 0 d. H0: μ < 0

H0: μ < 0

A soft drink filling machine, when in perfect adjustment, fills the bottles with 12 ounces of soft drink. Any overfilling or underfilling results in the shutdown and readjustment of the machine. To determine whether or not the machine is properly adjusted, the correct set of hypotheses is _____. a. H0: μ ≤ 12 Ha: μ > 12 b. H0: μ < 12 Ha: μ ≤ 12 c. H0: μ = 12 Ha: μ ≠ 12 d. H0: μ ≠ 12 Ha: μ = 12

H0: μ = 12 Ha: μ ≠ 12

When using Excel to calculate a p-value for a lower-tail hypothesis test, which of the following must be used? a. 1 − NORM.S.DIST b. RAND c. NORM.S.DIST d. Not enough information is given to answer this question.

NORM.S.DIST

A newspaper wants to estimate the proportion of Americans who will vote for Candidate A. A random sample of 1000 voters is selected. Of the 1000 respondents, 526 say that they will vote for Candidate A. Which Excel function would be used to construct a confidence interval estimate? a. NORM.S.INV b. T.INV c. INT d. NORM.INV

NORM.S.INV

Excel's __________ function can be used to calculate a p-value for a hypothesis test when σ is unknown. a. RAND b. NORM.S.DIST c. T.DIST d. Not enough information is given to answer this question.

T.DIST

From a population that is not normally distributed and whose standard deviation is not known, a sample of 50 items is selected to develop an interval estimate for μ. Which of the following statements is true? a. The t distribution with 49 degrees of freedom must be used. b. The t distribution with 50 degrees of freedom must be used. c. The sample size must be increased in order to develop an interval estimate. d. The standard normal distribution can be used.

The t distribution with 49 degrees of freedom must be used.

Exhibit 10-3 A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago. Final examination scores from a random sample of students enrolled today and from a random sample of students enrolled five years ago were selected. You are given the following information. Today Five Years Ago x̄ 82 88 σ 2 112.5 54 n 45 36 Refer to Exhibit 10-3. What conclusion can be reached about the difference in the average final examination scores between the two classes? (Use a .05 level of significance.) a. There is a statistically significant difference in the average final examination scores between the two classes. b. It is impossible to make a decision on the basis of the information given. c. There is no statistically significant difference in the average final examination scores between the two classes. d. There is a difference, but it is not significant.

There is a statistically significant difference in the average final examination scores between the two classes.

The error of rejecting a true null hypothesis is _____. a. a Type I error b. a Type II error c. committed when not enough information is available d. either a Type I or Type II error, depending on the situation

a Type I error

Whenever using the t distribution in interval estimation, we must assume that _____. a. the sample size is less than 30 b. the population is approximately normal c. a random sample was selected d. the finite population correction factor is necessary

a random sample was selected

A Type I error is committed when _____. a. a true alternative hypothesis is not accepted b. sample data contradict the null hypothesis c. the critical value is greater than the value of the test statistic d. a true null hypothesis is rejected

a true null hypothesis is rejected

If a hypothesis is not rejected at a 5% level of significance, it will _____. a. always be rejected at the 1% level b. sometimes be rejected at the 1% level c. also not be rejected at the 1% level d. Not enough information is given to answer this question.

also not be rejected at the 1% level

As a general guideline, the research hypothesis should be stated as the _____. a. tentative assumption b. alternative hypothesis c. null hypothesis d. hypothesis the researcher wants to disprove

alternative hypothesis

A 95% confidence interval for a population mean is determined to be 100 to 120. If the confidence coefficient is reduced to .90, the interval for μ _____. a. becomes wider b. does not change c. becomes .1 d. becomes narrower

becomes narrower

Using α = .04, a confidence interval for a population proportion is determined to be .65 to .75. If the level of significance is decreased, the interval for the population proportion _____. a. Not enough information is provided to answer this question. b. becomes narrower c. does not change d. becomes wider

becomes wider

When the level of confidence increases, the confidence interval _____. a. becomes narrower b. stays the same c. becomes wider d. Cannot be determined from the information given.

becomes wider

For a two-tailed test with a sample size of 40, the null hypothesis will NOT be rejected at a 5% level of significance if the test statistic is _____. a. greater than 1.96 b. less than 1.645 c. greater than -1.645 d. between -1.96 and 1.96, exclusively

between -1.96 and 1.96, exclusively

If two independent large samples are selected from two populations, the sampling distribution of the difference between the two sample means _____. a. can be approximated by a Poisson distribution b. can be approximated by a normal distribution c. will have a variance of 1 d. will have a mean of 1

can be approximated by a normal distribution

The probability that the interval estimation procedure will generate an interval that contains the actual value of the population parameter being estimated is the _____. a. error factor b. confidence level c. level of significance d. confidence coefficient

confidence coefficient

The confidence associated with an interval estimate is called the _____. a. confidence level b. precision c. level of significance d. degree of association

confidence level

To compute the minimum sample size for an interval estimate of μ when the population standard deviation is known, we must first determine all of the following EXCEPT _____. a. population standard deviation b. degrees of freedom c. desired margin of error d. confidence level

degrees of freedom

For a two-tailed hypothesis test about a population mean, the null hypothesis can be rejected if the confidence interval _____. a. is non-symmetric b. includes μ0 c. is symmetric d. does not include μ0

does not include μ0

For a one-tailed test (upper tail) with a sample size of 900, the null hypothesis will be rejected at the .05 level of significance if the test statistic is _____. a. greater than or equal to 1.645 b. less than 1.645 c. less than -1.96 d. less than or equal to -1.645

greater than or equal to 1.645

In tests about a population proportion, p0 represents the _____. a. hypothesized population proportion b. probability of p − p̄ c. observed sample proportion d. observed p-value

hypothesized population proportion

A two-tailed test is a hypothesis test in which the rejection region is _____. a. only in the upper tail of the sampling distribution b. only in the lower tail of the sampling distribution c. in both tails of the sampling distribution d. in one tail of the sampling distribution

in both tails of the sampling distribution

An estimate of a population parameter that provides an interval believed to contain the value of the parameter is known as the _____. a. interval estimate b. population estimate c. confidence level d. parameter value

interval estimate

To compute an interval estimate for the difference between the means of two populations, the t distribution _____. a. is not restricted to small sample situations b. is restricted to small sample situations c. can be applied when the populations have equal means d. None of these answers are correct.

is not restricted to small sample situations

When the rejection region is in the lower tail of the sampling distribution, the p-value is the area under the curve _____. a. greater than or equal to the test statistic b. greater than or equal to the critical value c. less than or equal to the critical value d. less than or equal to the test statistic

less than or equal to the test statistic

In a two-tailed hypothesis test, the null hypothesis should be rejected if the p-value is _____. a. greater than or equal to 2α b. less than or equal to 2α c. greater than or equal to α d. less than or equal to α

less than or equal to α

If the cost of a Type I error is high, a smaller value should be chosen for the _____. a. level of significance b. critical value c. test statistic d. confidence coefficient

level of significance

If a hypothesis is rejected at a 5% level of significance, it _____. a. will never be tested at the 1% level b. will always be rejected at the 1% level c. will always be accepted at the 1% level d. may be rejected or not rejected at the 1% level

may be rejected or not rejected at the 1% level

The sampling distribution of p̄1 - p̄2 is approximated by a _____. a. normal distribution b. t distribution with n1 + n2 degrees of freedom c. t distribution with n1 + n2 + 2 degrees of freedom d. t distribution with n1 + n2 - 1 degrees of freedom

normal distribution

Exhibit 9-3 n = 49 H0: μ = 50 x̄ = 54.8 Ha: μ ≠ 50 σ = 28 If the test is done at a 5% level of significance, the null hypothesis should _____. a. be rejected b. not be rejected c. Not enough information is given to answer this question. d. None of these answers are correct.

not be rejected

Exhibit 9-5 n = 16 H0: μ ≥ 80 x̄ = 75.607 Ha: μ < 80 σ = 8.246 Assume the population is normally distributed. If the test is done at a 2% level of significance, the null hypothesis should _____. a. be rejected b. not be rejected c. Not enough information is given to answer this question. d. None of these answers are correct.

not be rejected

Exhibit 9-4 A random sample of 16 students selected from the student body of a large university had an average age of 25 years. We want to determine if the average age of all the students at the university is significantly different from 24. Assume the distribution of the population of ages is normal with a standard deviation of 2 years. At a .05 level of significance, it can be concluded that the mean age is _____. a. not significantly different from 24 b. significantly different from 24 c. significantly less than 24 d. significantly less than 25

not significantly different from 24

Two approaches to drawing a conclusion in a hypothesis test are _____. a. one-tailed and two-tailed b. null and alternative c. p-value and critical value d. Type I and Type II

p-value and critical value

When the p-value is used for hypothesis testing, the null hypothesis is rejected if _____. a. p-value ≤ α b. p-value = z c. α < p-value d. p-value > α

p-value ≤ α

If the alternative hypothesis is that proportion of items in population 1 is larger than the proportion of items in population 2, then the null hypothesis should be _____. a. p1 - p2 > 0 b. p1 - p2 < 0 c. p1 - p2 = 0 d. p1 - p2 ≤ 0

p1 - p2 ≤ 0

The general form of an interval estimate of a population mean or population proportion is the _____ plus or minus the _____. a. point estimate, margin of error b. population mean, standard error c. level of significance, degrees of freedom d. planning value, confidence coefficient

point estimate, margin of error

A p-value is the _____. a. probability corresponding to the critical value(s) in a hypothesis test b. probability of a Type II error c. value of the test statistic d. probability, when the null hypothesis is true, of obtaining a sample result that is at least as unlikely as what is observed

probability, when the null hypothesis is true, of obtaining a sample result that is at least as unlikely as what is observed

The margin of error in an interval estimate of the population mean is a function of all of the following EXCEPT _____. a. level of significance b. variability of the population c. sample size d. sample mean

sample mean

Exhibit 10-9 Two major automobile manufacturers have produced compact cars with the same size engines. We are interested in determining whether or not there is a significant difference in the MPG (miles per gallon) of the two brands of automobiles. A random sample of eight cars from each manufacturer is selected, and eight drivers are selected to drive each automobile for a specified distance. The following data show the results of the test. Driver Manufacturer A Manufacturer B 1 32 28 2 27 22 3 26 27 4 26 24 5 25 24 6 29 25 7 31 28 8 25 27 Refer to Exhibit 10-9. At 90% confidence, the null hypothesis _____. a. should be revised b. should be rejected c. should not be rejected d. None of these answers are correct.

should be rejected

A two-tailed test is performed at a 5% level of significance. The p-value is determined to be .09. The null hypothesis _____. a. should not be rejected b. may or may not be rejected, depending on the sample size c. has been designed incorrectly d. must be rejected

should not be rejected

Whenever the population standard deviation is unknown, which distribution is used in developing an interval estimate for a population mean? a. z distribution b. standard distribution c. t distribution d. binomial distribution

t distribution

In hypothesis testing, if the null hypothesis has been rejected when the alternative hypothesis has been true, _____. a. either a Type I or Type II error has been committed b. a Type I error has been committed c. the correct decision has been made d. a Type II error has been committed

the correct decision has been made

In hypothesis testing if the null hypothesis is rejected, _____. a. the alternative hypothesis must also be rejected b. the evidence supports the alternative hypothesis c. the data must have been collected incorrectly d. no conclusions can be drawn from the test

the evidence supports the alternative hypothesis

In hypothesis testing, the alternative hypothesis is _____. a. the hypothesis tentatively assumed true in the hypothesis-testing procedure b. the hypothesis concluded to be true if the null hypothesis is rejected c. the maximum probability of a Type I error d. All of these answers are correct

the hypothesis concluded to be true if the null hypothesis is rejected

In the hypothesis testing procedure, α is _____. a. the confidence level b. the critical value c. 1 − level of significance d. the level of significance

the level of significance

Which of the following does NOT need to be known in order to compute the p-value? a. the value of the test statistic b. the level of significance c. knowledge of whether the test is one-tailed or two-tailed d. All of these answers are correct.

the level of significance

In determining the sample size necessary to estimate a population proportion, which of the following is NOT needed? a. a preliminary estimate of the true population proportion p b. the mean of the population c. the confidence level required d. the maximum margin of error that can be tolerated

the mean of the population

If a hypothesis test has a Type I error probability of .05, that means if the null hypothesis is _____. a. false, it will be rejected 5% of the time b. true, it will not be rejected 5% of the time c. false, it will not be rejected 5% of the time d. true, it will be rejected 5% of the time

true, it will be rejected 5% of the time

If we change a 95% confidence interval estimate to a 99% confidence interval estimate, we can expect the _____. a. width of the confidence interval to remain the same b. width of the confidence interval to increase c. sample size to increase d. width of the confidence interval to decrease

width of the confidence interval to increase

If the margin of error in an interval estimate of μ is 4.6, the interval estimate equals _____. a. x̄ ± 2.3 b. x̄ ± 4.508 c. x̄ ± 4.6 d. x̄ ± 6.9

x̄ ± 4.6

The probability of making a Type I error is denoted by _____. a. β b. 1 − α c. α d. 1 − β

α