Question 1

For a two-tailed test,a sample of 20 at 80% confidence,t =

Accepted Answer

A) 1.328 
B) 2.539 
C) 1.325 
D) 2.528 
A) 1.328 
B) 2.539 
C) 1.325 
D) 2.528 A

Question 2

You are given the following information obtained from a random sample of 4 observations.
   
You want to determine whether or not the mean of the population from which this sample was taken is significantly different from 48.(Assume the population is normally distributed. ) 
a.State the null and the alternative hypotheses.
b.Determine the test statistic.
c.Determine the p-value;and at 95% confidence test to determine whether or not the mean of the population is significantly different from 48.

Accepted Answer

a.H₀: $\mu$ = 48 H_a: $\mu$ $\neq$ 48 b.t = -1.137 c.p-value is between 0.2 and 0.4 (two tailed);do not reject H_0.

Question 3

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 B

Question 4

When the following hypotheses are being tested at a level of significance of $\alpha$
H0: $\mu$ 
Ha: $\mu$ < 500
The null hypothesis will be rejected if the p-value is

Accepted Answer

A) $\le$$\alpha$ 
B) > $\alpha$ 
C) > $\alpha$/2 
D) $\le$1 - $\alpha$/2 
A) $\le$$\alpha$ 
B) > $\alpha$ 
C) > $\alpha$/2 
D) $\le$1 - $\alpha$/2

Question 5

Exhibit 9-9
The sales of a grocery store had an average of $8,000 per day.The store introduced several advertising campaigns in order to increase sales.To determine whether or not the advertising campaigns have been effective in increasing sales,a sample of 64 days of sales was selected.It was found that the average was $8,300 per day.From past information,it is known that the standard deviation of the population is $1,200.
-Refer to Exhibit 9-9.The correct null hypothesis for this problem is

Accepted Answer

A) $\mu$   8000 
C) $\mu$  = 8000 
D) $\mu$  > 8250 
A) $\mu$   8000 
C) $\mu$  = 8000 
D) $\mu$  > 8250

Question 6

A soft drink filling machine,when in perfect adjustment,fills the bottles with 12 ounces of soft drink.A random sample of 49 bottles is selected,and the contents are measured.The sample yielded a mean content of 11.88 ounces with a standard deviation of 0.35 ounces.
a.Formulate the hypotheses to test to determine if the machine is in perfect adjustment.
b.Compute the value of the test statistic.
c.Compute the p-value and give your conclusion regarding the adjustment of the machine.Let $\alpha$  = .05.

Accepted Answer

a.H₀:@#LAT-DLM& = 12 H_a<

Question 7

Exhibit 9-8
The average gasoline price of one of the major oil companies in Europe has been $1.25 per liter.Recently,the company has undertaken several efficiency measures in order to reduce prices.Management is interested in determining whether their efficiency measures have actually reduced prices.A random sample of 49 of their gas stations is selected and the average price is determined to be $1.20 per liter.Furthermore,assume that the standard deviation of the population (   )is $0.14.
-Refer to Exhibit 9-8.The value of the test statistic for this hypothesis test is

Accepted Answer

A) 1.96 
B) 1.645 
C) -2.5 
D) -1.645 
A) 1.96 
B) 1.645 
C) -2.5 
D) -1.645

Question 8

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& >

Question 9

A soft drink filling machine,when in perfect adjustment,fills the bottles with 12 ounces of soft drink.Any over filling or under filling 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

Accepted Answer

A) H0: $\mu$  a: $\mu$ $\le$12 
B) H0: $\mu$ $\le$
12 Ha: $\mu$  > 12 
C) H0: $\mu$  $\neq$12 Ha: $\mu$  = 12 
D) H0: $\mu$  = 12 Ha: $\mu$ $\neq$ 12 
A) H0: $\mu$  a: $\mu$ $\le$12 
B) H0: $\mu$ $\le$
12 Ha: $\mu$  > 12 
C) H0: $\mu$  $\neq$12 Ha: $\mu$  = 12 
D) H0: $\mu$  = 12 Ha: $\mu$ $\neq$ 12

Question 10

The average starting salary of students who graduated from colleges of Business in 2009 was $48,400.A sample of 100 graduates of 2010 showed an average starting salary of $50,000.Assume the standard deviation of the population is known to be $8,000.We want to determine whether or not there has been a significant increase in the starting salaries.
a.State the null and alternative hypotheses to be tested.
b.Compute the test statistic.
c.The null hypothesis is to be tested at 95% confidence.Determine the critical value for this test.
d.What do you conclude?
e.Compute the p-value.

Accepted Answer

a.H_o: @#LAT-DLM& @#LAT-DLM& 48,400 H

Question 11

Exhibit 9-8
The average gasoline price of one of the major oil companies in Europe has been $1.25 per liter.Recently,the company has undertaken several efficiency measures in order to reduce prices.Management is interested in determining whether their efficiency measures have actually reduced prices.A random sample of 49 of their gas stations is selected and the average price is determined to be $1.20 per liter.Furthermore,assume that the standard deviation of the population (   )is $0.14.
-Refer to Exhibit 9-8.The p-value for this problem is

Accepted Answer

A) 0.4938 
B) 0.0062 
C) 0.0124 
D) 0.05 
A) 0.4938 
B) 0.0062 
C) 0.0124 
D) 0.05

Question 12

Consider the following hypothesis test:
Ho: P   0.8
Ha: P > 0.8
A sample of 400 provided a sample proportion of 0.853. 
a.Determine the standard error of the proportion.
b.Compute the value of the test statistic.
c.Determine the p-value;and at 95% confidence,test the above hypotheses.

Accepted Answer

a.0.02
b.Z = 2.65
c.

Question 13

A lathe is set to cut bars of steel into lengths of 6 centimeters.The lathe is considered to be in perfect adjustment if the average length of the bars it cuts is 6 centimeters.A sample of 121 bars is selected randomly and measured.It is determined that the average length of the bars in the sample is 6.08 centimeters with a standard deviation of 0.44 centimeters.
a.Formulate the hypotheses to determine whether or not the lathe is in perfect adjustment.
b.Compute the test statistic.
c.Using the p-value approach,what is your conclusion? Let $\alpha$ = .05.

Accepted Answer

a.H₀: @#LAT-DLM& = 6 H_a<

Question 14

As the test statistic becomes larger,the p-value

Accepted Answer

A) gets smaller 
B) becomes larger 
C) stays the same,since the sample size has not been changed 
D) becomes negative 
A) gets smaller 
B) becomes larger 
C) stays the same,since the sample size has not been changed 
D) becomes negative

Question 15

A sample of 64 account balances from a credit company showed an average daily balance of $1,040.The standard deviation of the population is known to be $200.We are interested in determining if the mean of all account balances (i.e. ,population mean)is significantly different from $1,000.
a.Develop the appropriate hypotheses for this problem.
b.Compute the test statistic.
c.Compute the p-value.
d.Using the p-value approach at 95% confidence,test the above hypotheses.
e.Using the critical value approach at 95% confidence,test the hypotheses.

Accepted Answer

a.H_o: @#LAT-DLM& = 1000 H_a:

Question 16

In order to test the following hypotheses at an $\alpha$ level of significance
H0: $\mu$ 
Ha: $\mu$ > 800
The null hypothesis will be rejected if the test statistic Z is

Accepted Answer

A) $\ge$Z$\alpha$ 
B) < Z$\alpha$ 
C) < -Z$\alpha$ 
D) = $\alpha$ 
A) $\ge$Z$\alpha$ 
B) < Z$\alpha$ 
C) < -Z$\alpha$ 
D) = $\alpha$

Question 17

The level of significance in hypothesis testing is the probability of

Accepted Answer

A) accepting a true null hypothesis 
B) accepting a false null hypothesis 
C) rejecting a true null hypothesis 
D) None of these alternatives is correct. 
A) accepting a true null hypothesis 
B) accepting a false null hypothesis 
C) rejecting a true null hypothesis 
D) None of these alternatives is correct.

Question 18

In order to determine the average price of hotel rooms in Atlanta,a sample of 64 hotels was selected.It was determined that the average price of the rooms in the sample was $108.50 with a standard deviation of $16.
a.Formulate the hypotheses to determine whether or not the average room price is significantly different from $112.
b.Compute the test statistic.
c.At 95% confidence using the p-value approach,test the hypotheses.Let $\alpha$  = 0.1.

Accepted Answer

a.H₀: @#LAT-DLM& = 112 H

Question 19

In a two-tailed hypothesis test situation,the test statistic is determined to be t = -2.692.The sample size has been 45.The p-value for this test is

Accepted Answer

A) -0.005 
B) +0.005 
C) -0.01 
D) +0.01 
A) -0.005 
B) +0.005 
C) -0.01 
D) +0.01

Question 20

The average hourly wage of computer programmers with 2 years of experience has been $21.80.Because of high demand for computer programmers,it is believed there has been a significant increase in the average wage of computer programmers.To test whether or not there has been an increase,the correct hypotheses to be tested are

Accepted Answer

A) H0: $\mu$ a: $\mu$ $\ge$ 21.80 
B) H0: $\mu$ = 21.80 Ha: $\mu$ $\neq$21.80 
C) H0: $\mu$ > 21.80 Ha: $\mu$ $\le$ 21.80 
D) H0: $\mu$ $\le$ 21.80 Ha: $\mu$  > 21.80 
A) H0: $\mu$ a: $\mu$ $\ge$ 21.80 
B) H0: $\mu$ = 21.80 Ha: $\mu$ $\neq$21.80 
C) H0: $\mu$ > 21.80 Ha: $\mu$ $\le$ 21.80 
D) H0: $\mu$ $\le$ 21.80 Ha: $\mu$  > 21.80

For a two-tailed test,a sample of 20 at 80% confidence,t =

The level of significance is the

A soft drink filling machine,when in perfect adjustment,fills the bottles with 12 ounces of soft drink.Any over filling or under filling 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

Consider the following hypothesis test: H_o: P 0.8 H_a: P > 0.8 A sample of 400 provided a sample proportion of 0.853. a.Determine the standard error of the proportion. b.Compute the value of the test statistic. c.Determine the p-value;and at 95% confidence,test the above hypotheses.

As the test statistic becomes larger,the p-value

The level of significance in hypothesis testing is the probability of

In a two-tailed hypothesis test situation,the test statistic is determined to be t = -2.692.The sample size has been 45.The p-value for this test is

Data and Statistics

Descriptive Statistics: Tabular and Graphical Presentations

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Statistical Inference About Means and Proportions With Two Populations

Inferences About Population Variances

Tests of Goodness of Fit and Independence

Analysis of Variance and Experimental Design

Simple Linear Regression

Multiple Regression

Regression Analysis: Model Building

Index Numbers

Forecasting

Nonparametric Methods

Statistical Methods for Quality Control

Decision Analysis

Sample Survey

Filters

Exam 9: Hypothesis Tests

For a two-tailed test,a sample of 20 at 80% confidence,t =

The level of significance is the

When the following hypotheses are being tested at a level of significance of α\alphaα H0: μ\muμ 500 Ha: μ\muμ < 500 The null hypothesis will be rejected if the p-value is

A soft drink filling machine,when in perfect adjustment,fills the bottles with 12 ounces of soft drink.Any over filling or under filling 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

Consider the following hypothesis test: Ho: P 0.8 Ha: P > 0.8 A sample of 400 provided a sample proportion of 0.853. a.Determine the standard error of the proportion. b.Compute the value of the test statistic. c.Determine the p-value;and at 95% confidence,test the above hypotheses.

As the test statistic becomes larger,the p-value

In order to test the following hypotheses at an α\alphaα level of significance H0: μ\muμ 800 Ha: μ\muμ > 800 The null hypothesis will be rejected if the test statistic Z is

The level of significance in hypothesis testing is the probability of

In a two-tailed hypothesis test situation,the test statistic is determined to be t = -2.692.The sample size has been 45.The p-value for this test is

Data and Statistics

Descriptive Statistics: Tabular and Graphical Presentations

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Statistical Inference About Means and Proportions With Two Populations

Inferences About Population Variances

Tests of Goodness of Fit and Independence

Analysis of Variance and Experimental Design

Simple Linear Regression

Multiple Regression

Regression Analysis: Model Building

Index Numbers

Forecasting

Nonparametric Methods

Statistical Methods for Quality Control

Decision Analysis

Sample Survey

Filters

Consider the following hypothesis test: H_o: P 0.8 H_a: P > 0.8 A sample of 400 provided a sample proportion of 0.853. a.Determine the standard error of the proportion. b.Compute the value of the test statistic. c.Determine the p-value;and at 95% confidence,test the above hypotheses.