Question 1

If the hypothesized proportion is π0 = .025 in a sample of size 120,it is safe to assume normality of the sample proportion p.

Accepted Answer

A) True 
 B)False

Question 2

The power of a test is the probability of

Accepted Answer

A) concluding H1 when H1 is true. 
B) concluding H1 when H0 is true. 
C) concluding H0 when H0 is true. 
D) concluding H0 when H1 is true. 
A) concluding H1 when H1 is true. 
B) concluding H1 when H0 is true. 
C) concluding H0 when H0 is true. 
D) concluding H0 when H1 is true.

Question 3

Which is an invalid alternative hypothesis?

Accepted Answer

A) H1: μ ≠ 18 B) H1: μ = 18 C) H1: μ > 18 D) H1: μ < 18 A) H1: μ ≠ 18 B) H1: μ = 18 C) H1: μ > 18 D) H1: μ < 18

Question 4

The process that produces Sonora Bars (a type of candy)is intended to produce bars with a mean weight of 56 gm.The process standard deviation is known to be 0.77 gm.A random sample of 49 candy bars yields a mean weight of 55.82 gm.Find the test statistic to see whether the candy bars are smaller than they are supposed to be.

Accepted Answer

A) −1.636 
B) −1.645 
C) −1.677 
A) −1.636 
B) −1.645 
C) −1.677

Question 5

For a given sample size,when we increase the probability of a Type I error,the probability of a Type II error

Accepted Answer

A) remains unchanged. 
B) increases. 
C) decreases. 
D) is impossible to determine without more information. 
A) remains unchanged. 
B) increases. 
C) decreases. 
D) is impossible to determine without more information.

Question 6

If the sample size increases from 25 to 100 and the level of significance stays the same,then

Accepted Answer

A) the risk of a Type II error would decrease. 
B) the risk of a Type I error would decrease. 
C) the risk of both Type I and Type II errors would decrease. 
D) the risk of neither Type I nor Type II error would decrease. 
A) the risk of a Type II error would decrease. 
B) the risk of a Type I error would decrease. 
C) the risk of both Type I and Type II errors would decrease. 
D) the risk of neither Type I nor Type II error would decrease.

Question 7

When the probability of a Type I error increases,the probability of a Type II error must decrease,ceteris paribus.

Accepted Answer

A) True 
 B)False

Question 8

A null hypothesis is rejected when the calculated p-value is less than the critical value of the test statistic.

Accepted Answer

A) True 
 B)False

Question 9

The level of significance refers to the probability of making a Type II error.

Accepted Answer

A) True 
 B)False

Question 10

Bob hypothesizes that the average student at his university has to take more than 130 credits to graduate.He takes a random sample of his classmates and performs a test.The results shown below are from MegaStat.What would Bob conclude from this test? Explain carefully.

Accepted Answer

The t-value is almost two standard error

Question 11

For a given H0 and level of significance,if you reject the H0 for a one-tailed test,you would also reject H0 for a two-tailed test.

Accepted Answer

A) True 
 B)False

Question 12

"My careful physical examination shows no evidence of any serious problem," said Doctor Morpheus."However,a very costly lab test can be performed to check for the rare condition known as estomalgia fatalis.The test is almost invariably negative for persons with your age and symptoms.My personal hypothesis is that the occasional stomach pain you reported is due to indigestion caused by eating tacos with too much hot sauce.But you must decide for yourself." As you consider your doctor's hypothesis,what would be the consequence of Type I error on your part?

Accepted Answer

A) It cannot be determined without knowing the type of test. 
B) Your estomalgia fatalis will go undetected. 
C) You will waste money on an unnecessary lab test. 
D) Your survivors will enjoy a sizeable malpractice award. 
A) It cannot be determined without knowing the type of test. 
B) Your estomalgia fatalis will go undetected. 
C) You will waste money on an unnecessary lab test. 
D) Your survivors will enjoy a sizeable malpractice award.

Question 13

Dullco Manufacturing claims that its alkaline batteries last at least 40 hours on average in a certain type of portable CD player.But tests on a random sample of 18 batteries from a day's large production run showed a mean battery life of 37.8 hours with a standard deviation of 5.4 hours.To test DullCo's hypothesis,the p-value is

Accepted Answer

A) slightly less than .05. 
B) exactly equal to .05. 
C) slightly greater than .05. 
D) uncertain without knowing α. 
A) slightly less than .05. 
B) exactly equal to .05. 
C) slightly greater than .05. 
D) uncertain without knowing α.

Question 14

John rejected H0,so we know definitely that he did not commit a Type II error.

Accepted Answer

A) True 
 B)False

Question 15

In a left-tailed test,a statistician got a z test statistic of −1.61.What is the p-value?

Accepted Answer

A) .4292 
B) .0709 
C) .0537 
D) .0301 
A) .4292 
B) .0709 
C) .0537 
D) .0301

Question 16

A two-tailed hypothesis test for H0: π = .30 at α = .05 is analogous to

Accepted Answer

A) asking if the 90 percent confidence interval for π contains .30. 
B) asking if the 95 percent confidence interval for π contains .30. 
C) asking if the p-value (area in both tails combined)is less than .025. 
D) asking if the p-value (area in both tails combined)is less than .10. 
A) asking if the 90 percent confidence interval for π contains .30. 
B) asking if the 95 percent confidence interval for π contains .30. 
C) asking if the p-value (area in both tails combined)is less than .025. 
D) asking if the p-value (area in both tails combined)is less than .10.

Question 17

The Melodic Kortholt Company will change its current health plan if at least half the employees are dissatisfied with it.A trial sample of 25 employees shows that 16 are dissatisfied.The p-value for a right-tailed test is

Accepted Answer

A) .1337 
B) .4192 
C) .0901 
D) .0808 
A) .1337 
B) .4192 
C) .0901 
D) .0808

Question 18

Compared to using α = .01,choosing α = .001 will make it less likely that a true null hypothesis will be rejected.

Accepted Answer

A) True 
 B)False

Question 19

Ajax Peanut Butter's quality control allows 2 percent of the jars to exceed the quality standard for insect fragments.A sample of 150 jars from the current day's production reveals that 30 exceed the quality standard for insect fragments.Which is incorrect?

Accepted Answer

A) Normality of p may safely be assumed in the hypothesis test. 
B) A right-tailed test would be appropriate. 
C) We strongly suspect that quality control standards are not met. 
D) Type II error is more of a concern in this case than Type I error. 
A) Normality of p may safely be assumed in the hypothesis test. 
B) A right-tailed test would be appropriate. 
C) We strongly suspect that quality control standards are not met. 
D) Type II error is more of a concern in this case than Type I error.

Question 20

For a given sample size,reducing the level of significance will decrease the probability of making a Type II error.

Accepted Answer

A) True 
 B)False

If the hypothesized proportion is π0 = .025 in a sample of size 120,it is safe to assume normality of the sample proportion p.

The power of a test is the probability of

Which is an invalid alternative hypothesis?

For a given sample size,when we increase the probability of a Type I error,the probability of a Type II error

If the sample size increases from 25 to 100 and the level of significance stays the same,then

When the probability of a Type I error increases,the probability of a Type II error must decrease,ceteris paribus.

A null hypothesis is rejected when the calculated p-value is less than the critical value of the test statistic.

The level of significance refers to the probability of making a Type II error.

Bob hypothesizes that the average student at his university has to take more than 130 credits to graduate.He takes a random sample of his classmates and performs a test.The results shown below are from MegaStat.What would Bob conclude from this test? Explain carefully.

For a given H0 and level of significance,if you reject the H0 for a one-tailed test,you would also reject H0 for a two-tailed test.

John rejected H0,so we know definitely that he did not commit a Type II error.

In a left-tailed test,a statistician got a z test statistic of −1.61.What is the p-value?

A two-tailed hypothesis test for H0: π = .30 at α = .05 is analogous to

The Melodic Kortholt Company will change its current health plan if at least half the employees are dissatisfied with it.A trial sample of 25 employees shows that 16 are dissatisfied.The p-value for a right-tailed test is

Compared to using α = .01,choosing α = .001 will make it less likely that a true null hypothesis will be rejected.

Ajax Peanut Butter's quality control allows 2 percent of the jars to exceed the quality standard for insect fragments.A sample of 150 jars from the current day's production reveals that 30 exceed the quality standard for insect fragments.Which is incorrect?

For a given sample size,reducing the level of significance will decrease the probability of making a Type II error.

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions and Estimation

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Chi-Square Tests

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Exam 9: One-Sample Hypothesis Tests

If the hypothesized proportion is π0 = .025 in a sample of size 120,it is safe to assume normality of the sample proportion p.

The power of a test is the probability of

Which is an invalid alternative hypothesis?

For a given sample size,when we increase the probability of a Type I error,the probability of a Type II error

If the sample size increases from 25 to 100 and the level of significance stays the same,then

When the probability of a Type I error increases,the probability of a Type II error must decrease,ceteris paribus.

A null hypothesis is rejected when the calculated p-value is less than the critical value of the test statistic.

The level of significance refers to the probability of making a Type II error.

Bob hypothesizes that the average student at his university has to take more than 130 credits to graduate.He takes a random sample of his classmates and performs a test.The results shown below are from MegaStat.What would Bob conclude from this test? Explain carefully.

For a given H0 and level of significance,if you reject the H0 for a one-tailed test,you would also reject H0 for a two-tailed test.

John rejected H0,so we know definitely that he did not commit a Type II error.

In a left-tailed test,a statistician got a z test statistic of −1.61.What is the p-value?

A two-tailed hypothesis test for H0: π = .30 at α = .05 is analogous to

The Melodic Kortholt Company will change its current health plan if at least half the employees are dissatisfied with it.A trial sample of 25 employees shows that 16 are dissatisfied.The p-value for a right-tailed test is

Compared to using α = .01,choosing α = .001 will make it less likely that a true null hypothesis will be rejected.

Ajax Peanut Butter's quality control allows 2 percent of the jars to exceed the quality standard for insect fragments.A sample of 150 jars from the current day's production reveals that 30 exceed the quality standard for insect fragments.Which is incorrect?

For a given sample size,reducing the level of significance will decrease the probability of making a Type II error.

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions and Estimation

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Chi-Square Tests

Filters