A marriage counselor has traditionally seen that the proportion p of all married couples for whom her communication program can prevent divorce is 80%. After making some recent changes, the marriage counselor now claims that her program can prevent divorce in more than 80% of married couples. In a random sample of 215 married couples who completed her program, 180 of them stayed together. Based on this sample, is there enough evidence to support the marriage counselor's claim at the 0.05 level of significance? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places. (If necessary, consult a list of formulas.)
A marriage counselor has traditionally seen that the proportion p of all married couples for whom her communication program can prevent divorce is 80%. After making some recent changes, the marriage counselor now claims that her program can prevent divorce in more than 80% of married couples. In a random sample of 215 married couples who completed her program, 180 of them stayed together. Based on this sample, is there enough evidence to support the marriage counselor's claim at the 0.05 level of significance? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places. (If necessary, consult a list of formulas.)
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
Related questions
Question

Transcribed Image Text:A marriage counselor has traditionally seen that the proportion \( p \) of all married couples for whom her communication program can prevent divorce is 80%. After making some recent changes, the marriage counselor now claims that her program can prevent divorce in more than 80% of married couples. In a random sample of 215 married couples who completed her program, 180 of them stayed together. Based on this sample, is there enough evidence to support the marriage counselor’s claim at the 0.05 level of significance?
Perform a one-tailed test. Then complete the parts below.
Carry your intermediate computations to three or more decimal places. (If necessary, consult a list of formulas.)
![## Finding the Value of the Test Statistic
The value of this test statistic is the z-value corresponding to the sample proportion under the assumption that \( H_0 \) is true. Here is the formula and calculation for determining the z-value:
\[ z = \frac{\hat{p} - p}{\sqrt{\frac{p(1-p)}{n}}} = \frac{\frac{36}{43} - 0.80}{\sqrt{\frac{0.80(1 - 0.80)}{215}}} \approx 1.364 \]
### Explanation:
- **Sample Proportion (\(\hat{p}\))**: The sample proportion is represented as \(\frac{36}{43}\).
- **Population Proportion (\(p\))**: The population proportion is given as 0.80.
- **Sample Size (\(n\))**: The sample size is 215.
The formula used to find the z-value is:
\[ z = \frac{\hat{p} - p}{\sqrt{\frac{p(1-p)}{n}}} \]
This equation subtracts the population proportion (\(p\)) from the sample proportion (\(\hat{p}\)) and divides by the standard error of the proportion, which is calculated as:
\[ \sqrt{\frac{p(1-p)}{n}} \]
By plugging in the given values:
\[ \hat{p} = \frac{36}{43} \approx 0.8372 \]
\[ p = 0.80 \]
\[ n = 215 \]
\[ z = \frac{0.8372 - 0.80}{\sqrt{\frac{0.80 \times (1 - 0.80)}{215}}} \]
Simplifying the denominator:
\[ \sqrt{\frac{0.80 \times 0.20}{215}} = \sqrt{\frac{0.16}{215}} = \sqrt{0.000744186} \approx 0.02728 \]
Now, putting everything together:
\[ z = \frac{0.8372 - 0.80}{0.02728} = \frac{0.0372}{0.02728} \approx 1.364 \]
Thus, the z-value is approximately **1.364**. This z-value can be used to determine the statistical significance under](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F715ecfc9-db17-4203-b60f-304ee331059c%2F5b02f7f7-1f7c-4e10-8a19-1bff29b9e218%2Fqbapqus_processed.png&w=3840&q=75)
Transcribed Image Text:## Finding the Value of the Test Statistic
The value of this test statistic is the z-value corresponding to the sample proportion under the assumption that \( H_0 \) is true. Here is the formula and calculation for determining the z-value:
\[ z = \frac{\hat{p} - p}{\sqrt{\frac{p(1-p)}{n}}} = \frac{\frac{36}{43} - 0.80}{\sqrt{\frac{0.80(1 - 0.80)}{215}}} \approx 1.364 \]
### Explanation:
- **Sample Proportion (\(\hat{p}\))**: The sample proportion is represented as \(\frac{36}{43}\).
- **Population Proportion (\(p\))**: The population proportion is given as 0.80.
- **Sample Size (\(n\))**: The sample size is 215.
The formula used to find the z-value is:
\[ z = \frac{\hat{p} - p}{\sqrt{\frac{p(1-p)}{n}}} \]
This equation subtracts the population proportion (\(p\)) from the sample proportion (\(\hat{p}\)) and divides by the standard error of the proportion, which is calculated as:
\[ \sqrt{\frac{p(1-p)}{n}} \]
By plugging in the given values:
\[ \hat{p} = \frac{36}{43} \approx 0.8372 \]
\[ p = 0.80 \]
\[ n = 215 \]
\[ z = \frac{0.8372 - 0.80}{\sqrt{\frac{0.80 \times (1 - 0.80)}{215}}} \]
Simplifying the denominator:
\[ \sqrt{\frac{0.80 \times 0.20}{215}} = \sqrt{\frac{0.16}{215}} = \sqrt{0.000744186} \approx 0.02728 \]
Now, putting everything together:
\[ z = \frac{0.8372 - 0.80}{0.02728} = \frac{0.0372}{0.02728} \approx 1.364 \]
Thus, the z-value is approximately **1.364**. This z-value can be used to determine the statistical significance under
Expert Solution

This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
This is a popular solution!
Trending now
This is a popular solution!
Step by step
Solved in 2 steps with 2 images

Recommended textbooks for you

MATLAB: An Introduction with Applications
Statistics
ISBN:
9781119256830
Author:
Amos Gilat
Publisher:
John Wiley & Sons Inc

Probability and Statistics for Engineering and th…
Statistics
ISBN:
9781305251809
Author:
Jay L. Devore
Publisher:
Cengage Learning

Statistics for The Behavioral Sciences (MindTap C…
Statistics
ISBN:
9781305504912
Author:
Frederick J Gravetter, Larry B. Wallnau
Publisher:
Cengage Learning

MATLAB: An Introduction with Applications
Statistics
ISBN:
9781119256830
Author:
Amos Gilat
Publisher:
John Wiley & Sons Inc

Probability and Statistics for Engineering and th…
Statistics
ISBN:
9781305251809
Author:
Jay L. Devore
Publisher:
Cengage Learning

Statistics for The Behavioral Sciences (MindTap C…
Statistics
ISBN:
9781305504912
Author:
Frederick J Gravetter, Larry B. Wallnau
Publisher:
Cengage Learning

Elementary Statistics: Picturing the World (7th E…
Statistics
ISBN:
9780134683416
Author:
Ron Larson, Betsy Farber
Publisher:
PEARSON

The Basic Practice of Statistics
Statistics
ISBN:
9781319042578
Author:
David S. Moore, William I. Notz, Michael A. Fligner
Publisher:
W. H. Freeman

Introduction to the Practice of Statistics
Statistics
ISBN:
9781319013387
Author:
David S. Moore, George P. McCabe, Bruce A. Craig
Publisher:
W. H. Freeman