close solutoin list

For each of the following, test for the significance of the difference in sample statistics using the five- step model. ( HINT : Remember to solve Formula 8.4 before attempting to solve Formula 8.2. Also, in Formula 8.4, perform the mathematical operations in the proper sequence. First square each sample standard deviation, then divide by the proper N , add the resultant values, and then find the square root of the sum. ) a. Sample 1 Sample 2 X ¯ 1 = 72.5 X ¯ 2 = 76.0 s 1 = 14.3 s 2 = 10.2 N 1 = 136 N 2 = 257 b. Sample 1 Sample 2 X ¯ 1 = 107 X ¯ 2 = 103 s 1 = 14 s 2 = 17 N 1 = 175 N 2 = 200

BuyFind

Essentials Of Statistics

4th Edition
HEALEY + 1 other
Publisher: Cengage Learning,
ISBN: 9781305093836
BuyFind

Essentials Of Statistics

4th Edition
HEALEY + 1 other
Publisher: Cengage Learning,
ISBN: 9781305093836

Solutions

Chapter
Section
Chapter 8, Problem 8.1P
Textbook Problem
243 views

For each of the following, test for the significance of the difference in sample statistics using the five- step model. (HINT: Remember to solve Formula 8.4 before attempting to solve Formula 8.2. Also, in Formula 8.4, perform the mathematical operations in the proper sequence. First square each sample standard deviation, then divide by the proper N , add the resultant values, and then find the square root of the sum.)

a.

Sample 1 Sample 2
X ¯ 1 = 72.5 X ¯ 2 = 76.0
s 1 = 14.3 s 2 = 10.2
N 1 = 136 N 2 = 257

b.

Sample 1 Sample 2
X ¯ 1 = 107 X ¯ 2 = 103
s 1 = 14 s 2 = 17
N 1 = 175 N 2 = 200

Expert Solution
To determine

(a)

To find:

The significant difference in the sample statistics for the two samples.

Answer to Problem 8.1P

Solution:

There is a significant difference between the sample statistics of two samples.

Explanation of Solution

Given:

The sample statistics is given in the table below,

Sample 1 Sample 2
X¯1=72.5 X¯2=76.0
s1=14.3 s2=10.2
N1=136 N2=257

The five step model for hypothesis testing:

Step 1. Making assumptions and meeting test requirements.

Step 2. Stating the null hypothesis.

Step 3. Selecting the sampling distribution and establishing the critical region.

Step 4. Computing test statistics.

Step 5. Making a decision and interpreting the results of the test.

Formula used:

The formula to calculate the sampling distribution of the differences in sample means is given by,

Z(obtained)=(X¯1X¯2)(μ1μ2)σX¯X¯

Where, X¯1 and X¯2 is the mean of first and second sample respectively,

μ1 and μ2 is the mean of first and second population respectively,

σX¯X¯ is the standard deviation and the formula to calculate σX¯X¯ is given by,

σX¯X¯=s21N11+s22N21

Where, N1 and N2 is the number of first and second population respectively.

Calculation:

From the given information, the sample size of the first sample is 136, the sample size of the second sample is 257, the sample mean of the first sample is 72.5, the sample mean of the second sample is 76.0, the sample standard deviation of the first sample is 14.3, and the sample standard deviation of the second sample is 10.2.

As the significant difference in the sample statistics is to be determined, a two tailed test is applied.

Follow the steps for two-sample testing as,

Step 1. Making assumptions and meeting test requirements.

Model:

Consider independent random samples.

Level of measurement is interval ratio.

Sampling distribution is Normal.

Step 2. State the null hypothesis.

The statement of the null hypothesis is that there is no significant difference in the sample s of the population. Thus, the null and the alternative hypotheses are,

H0:μ1=μ2

H1:μ1μ2

Step 3. Selecting the sampling distribution and establishing the critical region.

Since, the sample size is large, Z distribution can be used.

Thus, the sampling distribution is Z distribution.

The level of significance is,

α=0.05

Area of critical region is,

Z(critical)=±1.96

Step 4. Compute test statistics.

The population standard deviations are unknown.

The formula to calculate σX¯X¯ is given by,

σX¯X¯=s21N11+s22N21

Substitute 14.3 for s1, 10.2 for s2, 136 for N1, and 257 for N2 in the above mentioned formula,

σX¯X¯=(14.3)21361+(10.2)22571=204.49135+104.04256=1.5147+0.4064=1.9211

Simplify further,

σX¯X¯=1.38611.39(1)

The sampling distribution of the differences in sample means is given by,

Z(obtained)=(X¯1X¯2)(μ1μ2)σX¯X¯

Under the null hypotheses,

μ1μ2=0

Substitute 0 for μ1μ2 in the above mentioned formula,

Z(obtained)=(X¯1X¯2)σX¯X¯

From equation (1) substitute 72.5 for X¯1, 76.0 for X¯2, and 1.39 for σX¯X¯ in the above mentioned formula,

Z(obtained)=(72.576.0)1.39=3.51.39=2.52

Thus, the obtained Z value is 2.52.

Step 5. Making a decision and interpreting the results of the test.

Compare the test statistic with the critical Z value. The Z score falls in the rejection region. This implies that there is a significant difference between the two samples. The decision to reject the null hypothesis has only 0.05 probability of being incorrect.

Conclusion:

Therefore, there is a significant difference between the sample statistics of two samples.

Expert Solution
To determine

(b)

To find:

The significant difference in the sample statistics of the two samples.

Answer to Problem 8.1P

Solution:

There is a significant difference between the sample statistics of two samples.

Explanation of Solution

Given:

The sample statistics is given in the table below,

Sample 1 Sample 2
X¯1=107 X¯2=103
s1=14 s2=17
N1=175 N2=200

The five step model for hypothesis testing:

Step 1. Making assumptions and meeting test requirements.

Step 2. Stating the null hypothesis.

Step 3. Selecting the sampling distribution and establishing the critical region.

Step 4. Computing test statistics.

Step 5. Making a decision and interpreting the results of the test.

Formula used:

The formula to calculate the sampling distribution of the differences in sample means is given by,

Z(obtained)=(X¯1X¯2)(μ1μ2)σX¯X¯

Where, X¯1 and X¯2 is the mean of first and second sample respectively,

μ1 and μ2 is the mean of first and second population respectively,

σX¯X¯ is the standard deviation and the formula to calculate σX¯X¯ is given by,

σX¯X¯=s21N11+s22N21

Where, N1 and N2 is the number of first and second population respectively.

Calculation:

From the given information, the sample size of the first sample is 175, the sample size of the second sample is 200, the sample mean of the first sample is 107, the sample mean of the second sample is 103, the sample standard deviation of the first sample is 14, and the sample standard deviation of the second sample is 17.

As the significant difference in the sample statistics is to be determined, a two tailed test is applied.

Follow the steps for two-sample testing as,

Step 1. Making assumptions and meeting test requirements.

Model:

Consider independent random samples.

Level of measurement is interval ratio.

Sampling distribution is Normal.

Step 2. State the null hypothesis.

The statement of the null hypothesis is that there is no significant difference in the sample s of the population. Thus, the null and the alternative hypotheses are,

H0:μ1=μ2

H1:μ1μ2

Step 3. Selecting the sampling distribution and establishing the critical region.

Since, the sample size is large, Z distribution can be used.

Thus, the sampling distribution is Z distribution.

The level of significance is,

α=0.05

Area of critical region is,

Z(critical)=±1.96

Step 4. Compute test statistics.

The population standard deviations are unknown.

The formula to calculate σX¯X¯ is given by,

σX¯X¯=s21N11+s22N21

Substitute 14 for s1, 17 for s2, 175 for N1, and 200 for N2 in the above mentioned formula,

σX¯X¯=(14)21751+(17)22001=196174+289199=1.1264+1.4523=2.5787

Simplify further,

σX¯X¯=1.60581.61(2)

The sampling distribution of the differences in sample means is given by,

Z(obtained)=(X¯1X¯2)(μ1μ2)σX¯X¯

Under the null hypotheses,

μ1μ2=0

Substitute 0 for μ1μ2 in the above mentioned formula,

Z(obtained)=(X¯1X¯2)σX¯X¯

From equation (2) substitute 107 for X¯1, 103 for X¯2, and 1.61 for σX¯X¯ in the above mentioned formula,

Z(obtained)=(107103)1.61=41.61=2.48

Thus, the obtained Z value is 2.48.

Step 5. Making a decision and interpreting the results of the test.

Compare the test statistic with the critical Z value. The Z score falls in the rejection region. This implies that there is a significant difference between the two samples. The decision to reject the null hypothesis has only 0.05 probability of being incorrect.

Conclusion:

Therefore, there is a significant difference between the sample statistics of two samples.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!

Get Solutions

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!

Get Solutions

Additional Math Textbook Solutions

Find more solutions based on key concepts
Show solutions
In Exercises 63-68, use the graph of the function f to determine limxf(x) and limxf(x) 65.

Applied Calculus for the Managerial, Life, and Social Sciences: A Brief Approach

List all of the subsets of {a, b, c, d}.

Mathematical Excursions (MindTap Course List)

In Problems 5-14, solve for x by writing the equation in exponential form. 14. (to three decimal places)

Mathematical Applications for the Management, Life, and Social Sciences

Perform the indicated operation for the following. 28.9092216.41

Contemporary Mathematics for Business & Consumers

Evaluate 01(x+1x2)dx by interpreting it in terms of areas.

Single Variable Calculus: Early Transcendentals

Evaluate .

Study Guide for Stewart's Single Variable Calculus: Early Transcendentals, 8th

What can a researcher do if the treatment administered during the first B?

Research Methods for the Behavioral Sciences (MindTap Course List)

Loan Origination FeeLending institutions often charge fees for mortgages. One type of fee consists of closing c...

Functions and Change: A Modeling Approach to College Algebra (MindTap Course List)

Restaurant Advertising and Revenue. Data on advertising expenditures and revenue (in thousands of dollars) for ...

Modern Business Statistics with Microsoft Office Excel (with XLSTAT Education Edition Printed Access Card) (MindTap Course List)

Figure 2.R.4 is a portion of a direction field of a differential equation dy/dx = f (x, y). By hand, sketch two...

A First Course in Differential Equations with Modeling Applications (MindTap Course List)