Question 1

When a researcher fails to reject a false null hypothesis,a Type II error has been committed.

Accepted Answer

A) True 
 B)False

Question 2

Hypotheses are tentative explanations of a principle operating in nature.

Accepted Answer

A) True 
 B)False

Question 3

Suppose you are testing the null hypothesis that a population mean is less than or equal to 46,against the alternative hypothesis that the population mean is greater than 46.If the sample size is 25, $\sigma$ is known,and alpha = .01,the critical value of z is _______.

Accepted Answer

A) 1.645 
B) -1.645 
C) 1.28 
D) -2.33 
E) 2.33 
A) 1.645 
B) -1.645 
C) 1.28 
D) -2.33 
E) 2.33

Question 4

In performing a hypothesis test where the null hypothesis is that the population mean is 4.8 against the alternative hypothesis that the population mean is not equal to 4.8,a random sample of 25 items is selected.The sample mean is 4.1 and the sample standard deviation is 1.4.It can be assumed that the population is normally distributed.The observed "t" value for this problem is _______.

Accepted Answer

A) -12.5 
B) 12.5 
C) -2.5 
D) -0.7 
E) 0.7 
A) -12.5 
B) 12.5 
C) -2.5 
D) -0.7 
E) 0.7

Question 5

A coffee-dispensing machine is supposed to deliver 8 ounces of liquid into each paper cup,but a consumer believes that the actual mean amount is less.The consumer obtained a sample of 16 cups of the dispensed liquid with sample mean of 7.75 ounces and sample variance of 0.81 ounces.If the dispensed liquid delivered per cup is normally distributed,the appropriate decision at α=0.05 is

Accepted Answer

A) increase the sample size 
B) reduce the sample size 
C) fail to reject the 8-ounces claim 
D) maintain status quo 
E) reject the 8-ounces claim 
A) increase the sample size 
B) reduce the sample size 
C) fail to reject the 8-ounces claim 
D) maintain status quo 
E) reject the 8-ounces claim

Question 6

The weight of a USB flash drive is 30 grams and is normally distributed.Periodically,quality control inspectors at Dallas Flash Drives randomly select a sample of 17 USB flash drives.If the mean weight of the USB flash drives is too heavy or too light the machinery is shut down for adjustment; otherwise,the production process continues.The last sample showed a mean and standard deviation of 31.9 and 1.8 grams,respectively..The null hypothesis is ______.

Accepted Answer

A) n $\neq$ 17 
B) n = 17 
C) $\mu$ = 30 
D) $\mu$ $\neq$ 30 
E) m ≥ 34.9 
A) n $\neq$ 17 
B) n = 17 
C) $\mu$ = 30 
D) $\mu$ $\neq$ 30 
E) m ≥ 34.9

Question 7

When a true null hypothesis is rejected,the researcher has made a Type I error.

Accepted Answer

A) True 
 B)False

Question 8

A researcher is testing a hypothesis of a single mean.The critical z value for $\alpha$ = .05 and a two?tailed test is +1.96.The observed z value from sample data is ?1.85.The decision made by the researcher based on this information is to _____ the null hypothesis.

Accepted Answer

A) reject 
B) fail to reject 
C) redefine 
D) change the alternate hypothesis into 
E) restate the null hypothesis 
A) reject 
B) fail to reject 
C) redefine 
D) change the alternate hypothesis into 
E) restate the null hypothesis

Question 9

David Desreumaux,VP of Human Resources of American First Banks (AFB),is reviewing the employee training programs of AFB banks.Based on a recent census of personnel,David knows that the variance of teller training time in the Southeast region is 8,and he wonders if the variance in the Southwest region is the same number.His staff randomly selected personnel files for 15 tellers in the Southwest Region,and determined that their mean training time was 25 hours and that the standard deviation was 4 hours.Assume that teller training time is normally distributed.Using $\alpha$ = 0.10,the observed value of chi-square is ________.

Accepted Answer

A) 28.00 
B) 30.00 
C) 56.00 
D) 60.00 
E) 65.00 
A) 28.00 
B) 30.00 
C) 56.00 
D) 60.00 
E) 65.00

Question 10

The null and the alternative hypotheses must be mutually exclusive and collectively exhaustive.

Accepted Answer

A) True 
 B)False

Question 11

The lifetime of a squirrel follows a normal distribution with mean μ months and a standard deviation  $\sigma$=7 months.To test the alternative hypothesis that μ > 40,25 squirrels are randomly selected.The null hypothesis is rejected when the sample mean is bigger than 43.Assuming that μ=45,the probability of type II error is approximately

Accepted Answer

A) 0.076 
B) 0.016 
C) 0.05 
D) 0.011 
E) 0.983 
A) 0.076 
B) 0.016 
C) 0.05 
D) 0.011 
E) 0.983

Question 12

In performing hypothesis tests about the population mean,if the population standard deviation is not known,a t test can be used to test the mean if _________________.

Accepted Answer

A) n is small 
B) the sample is random 
C) the population mean is known 
D) the population is normally distributed 
E) the population is chi-square distributed 
A) n is small 
B) the sample is random 
C) the population mean is known 
D) the population is normally distributed 
E) the population is chi-square distributed

Question 13

Discrete Components,Inc.manufactures a line of electrical resistors.Presently,the carbon composition line is producing 100 ohm resistors.The population variance of these resistors "must not exceed 4" to conform to industry standards.Periodically,the quality control inspectors check for conformity by randomly select 10 resistors from the line,and calculating the sample variance.The last sample had a variance of 4.36.Assume that the population is normally distributed.Using $\alpha$ = 0.05,the observed value of chi-square is _________________.

Accepted Answer

A) 1.74 
B) 1.94 
C) 10.90 
D) 9.81 
E) 8.91 
A) 1.74 
B) 1.94 
C) 10.90 
D) 9.81 
E) 8.91

Question 14

The weight of a USB flash drive is 30 grams and is normally distributed.Periodically,quality control inspectors at Dallas Flash Drives randomly select a sample of 17 USB flash drives.If the mean weight of the USB flash drives is too heavy or too light the machinery is shut down for adjustment; otherwise,the production process continues.The last sample showed a mean and standard deviation of 31.9 and 1.8 grams,respectively.Using $\alpha$ = 0.10,the appropriate decision is _______.

Accepted Answer

A) reject the null hypothesis and shut down the process 
B) reject the null hypothesis and do not shut down the process 
C) fail to reject the null hypothesis and shut down the process 
D) fail to reject the null hypothesis and do not shut down the processe)do nothing 
A) reject the null hypothesis and shut down the process 
B) reject the null hypothesis and do not shut down the process 
C) fail to reject the null hypothesis and shut down the process 
D) fail to reject the null hypothesis and do not shut down the processe)do nothing

Question 15

The local swim team is considering offering a new semi-private class aimed at entry-level swimmers,but needs at minimum number of swimmers to sign up in order to be cost effective.Last year's data showed that during 8 swim sessions the average number of entry-level swimmers attending was 15.Suppose the instructor wants to conduct a hypothesis test.The alternative hypothesis for this hypothesis test is: "the population mean is less than 15".The sample size is 8, $\sigma$ is known,and alpha =.05,the critical value of z is _______.

Accepted Answer

A) 1.645 
B) -1.645 
C) 1.96 
D) -1.96 
E) 2.05 
A) 1.645 
B) -1.645 
C) 1.96 
D) -1.96 
E) 2.05

Question 16

In testing hypotheses,the researcher initially assumes that the alternative hypothesis is true and uses the sample data to reject it.

Accepted Answer

A) True 
 B)False

Question 17

A z test of proportions is used when a hypothesis test is conducted on a population proportion.

Accepted Answer

A) True 
 B)False

Question 18

The rejection region for a hypothesis test becomes smaller if the level of significance is changed from 0.01 to 0.05.

Accepted Answer

A) True 
 B)False

Question 19

The lifetime of a squirrel follows a normal distribution with mean μ = 40 months and a standard deviation  $\sigma$=7 months.To test the hypothesis that μ>40,25 squirrels are randomly selected.Assuming that μ=45,and α=0.1,the probability of type II error is approximately

Accepted Answer

A) 0.076 
B) 0.016 
C) 0.05 
D) 0.011 
E) 0.983 
A) 0.076 
B) 0.016 
C) 0.05 
D) 0.011 
E) 0.983

Question 20

David Desreumaux,VP of Human Resources of American First Banks (AFB),is reviewing the employee training programs of AFB banks.Based on a recent census of personnel,David knows that the variance of teller training time in the Southeast region is 8,and he wonders if the variance in the Southwest region is the same number.His staff randomly selected personnel files for 15 tellers in the Southwest Region,and determined that their mean training time was 25 hours and that the standard deviation was 4 hours.Assume that teller training time is normally distributed.Using $\alpha$ = 0.10,the critical values of chi-square are ________.

Accepted Answer

A) 7.96 and 26.30 
B) 6.57 and 23.68 
C) -1.96 and 1.96 
D) -1.645 and 1.645 
E) -6.57 and 23.68 
A) 7.96 and 26.30 
B) 6.57 and 23.68 
C) -1.96 and 1.96 
D) -1.645 and 1.645 
E) -6.57 and 23.68

When a researcher fails to reject a false null hypothesis,a Type II error has been committed.

Hypotheses are tentative explanations of a principle operating in nature.

Suppose you are testing the null hypothesis that a population mean is less than or equal to 46,against the alternative hypothesis that the population mean is greater than 46.If the sample size is 25, $\sigma$ is known,and alpha = .01,the critical value of z is _______.

When a true null hypothesis is rejected,the researcher has made a Type I error.

A researcher is testing a hypothesis of a single mean.The critical z value for $\alpha$ = .05 and a two?tailed test is +1.96.The observed z value from sample data is ?1.85.The decision made by the researcher based on this information is to _____ the null hypothesis.

The null and the alternative hypotheses must be mutually exclusive and collectively exhaustive.

In performing hypothesis tests about the population mean,if the population standard deviation is not known,a t test can be used to test the mean if _________________.

In testing hypotheses,the researcher initially assumes that the alternative hypothesis is true and uses the sample data to reject it.

A z test of proportions is used when a hypothesis test is conducted on a population proportion.

The rejection region for a hypothesis test becomes smaller if the level of significance is changed from 0.01 to 0.05.

The lifetime of a squirrel follows a normal distribution with mean μ = 40 months and a standard deviation $\sigma$ =7 months.To test the hypothesis that μ>40,25 squirrels are randomly selected.Assuming that μ=45,and α=0.1,the probability of type II error is approximately

Introduction to Statistics

Charts and Graphs

Descriptive Statistics

Probability

Discrete Distributions

Continuous Distributions

Sampling and Sampling Distributions

Statistical Inference: Estimation for Single Populations

Statistical Inferences About Two Populations

Analysis of Variance and Design of Experiments

Simple Regression Analysis and Correlation

Multiple Regression Analysis

Building Multiple Regression Models

Time-Series Forecasting and Index Numbers

Analysis of Categorical Data

Nonparametric Statistics

Statistical Quality Control

Decision Analysis

Filters

Exam 9: Statistical Inference: Hypothesis Testing for Single Populations

When a researcher fails to reject a false null hypothesis,a Type II error has been committed.

Hypotheses are tentative explanations of a principle operating in nature.

Suppose you are testing the null hypothesis that a population mean is less than or equal to 46,against the alternative hypothesis that the population mean is greater than 46.If the sample size is 25, σ\sigmaσ is known,and alpha = .01,the critical value of z is _______.

When a true null hypothesis is rejected,the researcher has made a Type I error.

A researcher is testing a hypothesis of a single mean.The critical z value for α\alphaα = .05 and a two?tailed test is +1.96.The observed z value from sample data is ?1.85.The decision made by the researcher based on this information is to _____ the null hypothesis.

The null and the alternative hypotheses must be mutually exclusive and collectively exhaustive.

In performing hypothesis tests about the population mean,if the population standard deviation is not known,a t test can be used to test the mean if _________________.

In testing hypotheses,the researcher initially assumes that the alternative hypothesis is true and uses the sample data to reject it.

A z test of proportions is used when a hypothesis test is conducted on a population proportion.

The rejection region for a hypothesis test becomes smaller if the level of significance is changed from 0.01 to 0.05.

The lifetime of a squirrel follows a normal distribution with mean μ = 40 months and a standard deviation σ\sigmaσ =7 months.To test the hypothesis that μ>40,25 squirrels are randomly selected.Assuming that μ=45,and α=0.1,the probability of type II error is approximately

Introduction to Statistics

Charts and Graphs

Descriptive Statistics

Probability

Discrete Distributions

Continuous Distributions

Sampling and Sampling Distributions

Statistical Inference: Estimation for Single Populations

Statistical Inferences About Two Populations

Analysis of Variance and Design of Experiments

Simple Regression Analysis and Correlation

Multiple Regression Analysis

Building Multiple Regression Models

Time-Series Forecasting and Index Numbers

Analysis of Categorical Data

Nonparametric Statistics

Statistical Quality Control

Decision Analysis

Filters

Suppose you are testing the null hypothesis that a population mean is less than or equal to 46,against the alternative hypothesis that the population mean is greater than 46.If the sample size is 25, $\sigma$ is known,and alpha = .01,the critical value of z is _______.

A researcher is testing a hypothesis of a single mean.The critical z value for $\alpha$ = .05 and a two?tailed test is +1.96.The observed z value from sample data is ?1.85.The decision made by the researcher based on this information is to _____ the null hypothesis.

The lifetime of a squirrel follows a normal distribution with mean μ = 40 months and a standard deviation $\sigma$ =7 months.To test the hypothesis that μ>40,25 squirrels are randomly selected.Assuming that μ=45,and α=0.1,the probability of type II error is approximately