Question 1

The probability of committing a Type I error when the null hypothesis is true is

Accepted Answer

A) the confidence level 
B) $\beta$ 
C) greater than 1 
D) the Level of Significance 
A) the confidence level 
B) $\beta$ 
C) greater than 1 
D) the Level of Significance

Question 2

A Type II error is committed when

Accepted Answer

A) a true alternative hypothesis is mistakenly rejected 
B) a true null hypothesis is mistakenly rejected 
C) the sample size has been too small 
D) not enough information has been available 
A) a true alternative hypothesis is mistakenly rejected 
B) a true null hypothesis is mistakenly rejected 
C) the sample size has been too small 
D) not enough information has been available

Question 3

A producer of various kinds of batteries has been producing "D" size batteries with a life expectancy of 87 hours. Due to an improved production process, management believes that there has been an increase in the life expectancy of their "D" size batteries. A sample of 36 batteries showed an average life of 88.5 hours. Assume from past information that it is known that the standard deviation of the population is 9 hours.
a.Give the null and the alternative hypotheses.
b.Compute the test statistic.
c.At 99% confidence using the critical value approach, test management's belief.
d.What is the p-value associated with the sample results? What is your conclusion based on the p-value?

Accepted Answer

a.H_o: @#LAT-DLM& < 87 H_a: @#LAT-DLM& > 87 b.1.00 c.S

Question 4

For a two-tailed test at 98.4% confidence, Z =

Accepted Answer

A) 1.96 
B) 1.14 
C) 2.41 
D) 0.8612 
A) 1.96 
B) 1.14 
C) 2.41 
D) 0.8612

Question 5

We are interested in conducting a study in order to determine what percentage of voters in a city would vote for the incumbent mayor. What is the minimum size sample needed to estimate the population proportion with a margin of error not exceeding 4% at 95% confidence?

Accepted Answer

A) 625 
B) 626 
C) 600 
D) 601 
A) 625 
B) 626 
C) 600 
D) 601

Question 6

Exhibit 9-6
A random sample of 16 students selected from the student body of a large university had an average age of 25 years and a standard deviation of 2 years. We want to determine if the average age of all the students at the university is significantly more than 24. Assume the distribution of the population of ages is normal.
-Refer to Exhibit 9-6. The p-value is between

Accepted Answer

A) .005 to .01 
B) .01 to .025 
C) .025 to .05 
D) .05 to .10 
A) .005 to .01 
B) .01 to .025 
C) .025 to .05 
D) .05 to .10

Question 7

When the p-value is used for hypothesis testing, the null hypothesis is rejected if

Accepted Answer

A) p-value   $\alpha$ 
B) $\alpha$ < p-value 
C) p-value   $\alpha$ 
D) p-value = 1 - $\alpha$ 
A) p-value   $\alpha$ 
B) $\alpha$ < p-value 
C) p-value   $\alpha$ 
D) p-value = 1 - $\alpha$

Question 8

At a local university, a sample of 49 evening students was selected in order to determine whether the average age of the evening students is significantly different from 21. The average age of the students in the sample was 23 with a standard deviation of 3.5.
a.Formulate the hypotheses for this problem.
b.Compute the test statistic.
c.Determine the p-value and test these hypotheses. Let $\alpha$ = .05.

Accepted Answer

a.H₀: @#LAT-DLM&= 21 H_a: @#LAT-DLM&@#LAT-DLM& 21 b.t

Question 9

The level of significance is the

Accepted Answer

A) maximum allowable probability of Type II error 
B) maximum allowable probability of Type I error 
C) same as the confidence coefficient 
D) same as the p-value 
A) maximum allowable probability of Type II error 
B) maximum allowable probability of Type I error 
C) same as the confidence coefficient 
D) same as the p-value

Question 10

It is known that the population variance ($\sigma$2) is 144. At 95% confidence, what size sample should be taken so that the margin of error is does not exceed 5 or less?

Accepted Answer

A) 22 
B) 23 
C) 24 
D) 25 
A) 22 
B) 23 
C) 24 
D) 25

Question 11

If the probability of a Type I error ($\alpha$) is 0.05, then the probability of a Type II error ($\beta$) must be

Accepted Answer

A) 0.05 
B) 0.95 
C) 0.025 
D) None of these alternatives is correct. 
A) 0.05 
B) 0.95 
C) 0.025 
D) None of these alternatives is correct.

Question 12

Exhibit 9-1
n = 36   = 24.6
S = 12
HS1U1B10S1U1B0: $\mu$  20
HS1U1B1aS1U1B0: $\mu$> 20
-Refer to Exhibit 9-1. If the test is done at 95% confidence, the null hypothesis should

Accepted Answer

A) not be rejected 
B) be rejected 
C) Not enough information is given to answer this question. 
D) None of these alternatives is correct. 
A) not be rejected 
B) be rejected 
C) Not enough information is given to answer this question. 
D) None of these alternatives is correct.

Question 13

The academic planner of a university thinks that at least 35% of the entire student body attends summer school. The correct set of hypotheses to test his belief is

Accepted Answer

A) H0: P > 0.35 Ha: P   0.35 
B) H0: P   0.35 Ha: P > 0.35 
C) H0: P   0.35 Ha: P 0: P > 0.35 Ha: P   0.35 
A) H0: P > 0.35 Ha: P   0.35 
B) H0: P   0.35 Ha: P > 0.35 
C) H0: P   0.35 Ha: P 0: P > 0.35 Ha: P   0.35

Question 14

In the last presidential election, a national survey company claimed that no more than 50% (i.e., < 50%) of all registered voters voted for the Republican candidate. In a random sample of 400 registered voters, 208 voted for the Republican candidate.
a.State the null and the alternative hypotheses.
b.Compute the test statistic.
c.At 95% confidence, compute the p-value and test the hypotheses.

Accepted Answer

a.H₀: P @#IMG-DLM& 0.5 H_a: P > 0

Question 15

Automobiles manufactured by the Efficiency Company have been averaging 42 miles per gallon of gasoline in highway driving. It is believed that its new automobiles average more than 42 miles per gallon. An independent testing service road-tested 36 of the automobiles. The sample showed an average of 42.8 miles per gallon with a standard deviation of 1.2 miles per gallon.
a.With a 0.05 level of significance using the critical value approach, test to determine whether or not the new automobiles actually do average more than 42 miles per gallon.
b.What is the p-value associated with the sample results? What is your conclusion based on the p-value?

Accepted Answer

a.H_o:@#LAT-DLM&< 42 H_a: @#LAT-DLM& > 42 Since t = 4.0 > 1.690,

Question 16

Read the Z statistic from the normal distribution table and circle the correct answer. A one-tailed test (upper tail) at 87.7% confidence; Z =

Accepted Answer

A) 1.54 
B) 1.96 
C) 1.645 
D) 1.16 
A) 1.54 
B) 1.96 
C) 1.645 
D) 1.16

Question 17

Exhibit 9-5
A random sample of 100 people was taken. Eighty-five 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 80%.
-Refer to Exhibit 9-5. The p-value is

Accepted Answer

A) 0.2112 
B) 0.05 
C) 0.025 
D) 0.1056 
A) 0.2112 
B) 0.05 
C) 0.025 
D) 0.1056

Question 18

Last year, a soft drink manufacturer had 21% of the market. In order to increase their portion of the market, the manufacturer has introduced a new flavor in their soft drinks. A sample of 400 individuals participated in the taste test and 100 indicated that they like the taste. We are interested in determining if more than 21% of the population will like the new soft drink.
a.Set up the null and the alternative hypotheses.
b.Determine the test statistic.
c.Determine the p-value.
d.At 95% confidence, test to determine if more than 21% of the population will like the new soft drink.

Accepted Answer

a.H₀: p @#IMG-DLM& 0.21 H_a: p > 0.21 b.Tes

Question 19

Choo Choo Paper Company makes various types of paper products. One of their products is a 30 mils thick paper. In order to ensure that the thickness of the paper meets the 30 mils specification, random cuts of paper are selected and the thickness of each cut is measured. A sample of 256 cuts had a mean thickness of 30.3 mils with a standard deviation of 4 mils.
a.Compute the standard error of the mean.
b.
b.At 95% confidence using the critical value approach, test to see if the mean thickness is significantly more than 30 mils.
c.Show that the p-value approach results in the same conclusion as that of part

Accepted Answer

a.0.25
b.Test statistics t = 1

Question 20

In hypothesis testing,

Accepted Answer

A) the smaller the Type I error, the smaller the Type II error will be 
B) the smaller the Type I error, the larger the Type II error will be 
C) Type II error will not be effected by Type I error 
D) the sum of Type I and Ttype II errors must equal to 1 
A) the smaller the Type I error, the smaller the Type II error will be 
B) the smaller the Type I error, the larger the Type II error will be 
C) Type II error will not be effected by Type I error 
D) the sum of Type I and Ttype II errors must equal to 1

The probability of committing a Type I error when the null hypothesis is true is

A Type II error is committed when

For a two-tailed test at 98.4% confidence, Z =

We are interested in conducting a study in order to determine what percentage of voters in a city would vote for the incumbent mayor. What is the minimum size sample needed to estimate the population proportion with a margin of error not exceeding 4% at 95% confidence?

When the p-value is used for hypothesis testing, the null hypothesis is rejected if

The level of significance is the

It is known that the population variance ( $\sigma$ ²) is 144. At 95% confidence, what size sample should be taken so that the margin of error is does not exceed 5 or less?

If the probability of a Type I error ( $\alpha$ ) is 0.05, then the probability of a Type II error ( $\beta$ ) must be

The academic planner of a university thinks that at least 35% of the entire student body attends summer school. The correct set of hypotheses to test his belief is

Read the Z statistic from the normal distribution table and circle the correct answer. A one-tailed test (upper tail) at 87.7% confidence; Z =

Exhibit 9-5 A random sample of 100 people was taken. Eighty-five 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 80%. -Refer to Exhibit 9-5. The p-value is

In hypothesis testing,

Data and Statistics

Descriptive Statistics: Tabular and Graphical Displays

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Inference About Means and Proportions With Two Populations

Inferences About Population Variances

Comparing Multiple Proportions, Test of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

Simple Linear Regression

Multiple Regression

Regression Analysis: Model Building

Time Series Analysis and Forecasting

Nonparametric Methods

Statistical Methods for Quality Control

Index Numbers

Decision Analysis on Website

Sample Survey on Website

Filters

Exam 9: Hypothesis Tests

The probability of committing a Type I error when the null hypothesis is true is

A Type II error is committed when

For a two-tailed test at 98.4% confidence, Z =

We are interested in conducting a study in order to determine what percentage of voters in a city would vote for the incumbent mayor. What is the minimum size sample needed to estimate the population proportion with a margin of error not exceeding 4% at 95% confidence?

When the p-value is used for hypothesis testing, the null hypothesis is rejected if

The level of significance is the

It is known that the population variance ( σ\sigmaσ 2) is 144. At 95% confidence, what size sample should be taken so that the margin of error is does not exceed 5 or less?

If the probability of a Type I error ( α\alphaα ) is 0.05, then the probability of a Type II error ( β\betaβ ) must be

Exhibit 9-1 n = 36 = 24.6 S = 12 H0: μ\muμ 20 Ha: μ\muμ > 20 -Refer to Exhibit 9-1. If the test is done at 95% confidence, the null hypothesis should

The academic planner of a university thinks that at least 35% of the entire student body attends summer school. The correct set of hypotheses to test his belief is

Read the Z statistic from the normal distribution table and circle the correct answer. A one-tailed test (upper tail) at 87.7% confidence; Z =

Exhibit 9-5 A random sample of 100 people was taken. Eighty-five 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 80%. -Refer to Exhibit 9-5. The p-value is

In hypothesis testing,

Data and Statistics

Descriptive Statistics: Tabular and Graphical Displays

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Inference About Means and Proportions With Two Populations

Inferences About Population Variances

Comparing Multiple Proportions, Test of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

Simple Linear Regression

Multiple Regression

Regression Analysis: Model Building

Time Series Analysis and Forecasting

Nonparametric Methods

Statistical Methods for Quality Control

Index Numbers

Decision Analysis on Website

Sample Survey on Website

Filters

It is known that the population variance ( $\sigma$ ²) is 144. At 95% confidence, what size sample should be taken so that the margin of error is does not exceed 5 or less?

If the probability of a Type I error ( $\alpha$ ) is 0.05, then the probability of a Type II error ( $\beta$ ) must be