Your professor wants to determine if her students today are performing better in statistics than 10 years ago. End of semester grades from a random sample of students enrolled today and one of students enrolled 10 years ago have been obtained: Today 10 Years Ago 82 88 112.5 54 o2 45 36 n Refer to Exhibit GGC 2-2. The test statistic for the difference between the two population means is a) -47 b) -.65 c) -3 d) -1.5
Your professor wants to determine if her students today are performing better in statistics than 10 years ago. End of semester grades from a random sample of students enrolled today and one of students enrolled 10 years ago have been obtained: Today 10 Years Ago 82 88 112.5 54 o2 45 36 n Refer to Exhibit GGC 2-2. The test statistic for the difference between the two population means is a) -47 b) -.65 c) -3 d) -1.5
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
![### Statistical Performance Comparison Over Time
Your professor wants to determine if her students today are performing better in statistics than 10 years ago. End of semester grades from a random sample of students enrolled today and one of students enrolled 10 years ago have been obtained:
| | Today | 10 Years Ago |
|----------------|-------|--------------|
| Mean (\( \bar{x} \)) | 82 | 88 |
| Variance (\( \sigma^2 \)) | 112.5 | 54 |
| Sample Size (\( n \)) | 45 | 36 |
Refer to Exhibit GGC 2-2. The test statistic for the difference between the two population means is ____.
**Options:**
- a) \(-.47\)
- b) \(-.65\)
- c) \(-3\)
- d) \(-1.5\)
### Explanation
To find the test statistic for the differences between the two means, use the formula for the two-sample Z-test:
\[
Z = \frac{(\bar{x}_1 - \bar{x}_2)}{\sqrt{\frac{\sigma_1^2}{n_1} + \frac{\sigma_2^2}{n_2}}}
\]
Where:
- \( \bar{x}_1 \) and \( \bar{x}_2 \) are the sample means
- \( \sigma_1^2 \) and \( \sigma_2^2 \) are the sample variances
- \( n_1 \) and \( n_2 \) are the sample sizes
Substitute in the given values to calculate the Z value and select the correct option.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F82e15764-9e28-4062-abb6-3148bc200de3%2F5d26b4a5-33dd-426a-a25f-79304180469a%2Fui9zzq_processed.png&w=3840&q=75)
Transcribed Image Text:### Statistical Performance Comparison Over Time
Your professor wants to determine if her students today are performing better in statistics than 10 years ago. End of semester grades from a random sample of students enrolled today and one of students enrolled 10 years ago have been obtained:
| | Today | 10 Years Ago |
|----------------|-------|--------------|
| Mean (\( \bar{x} \)) | 82 | 88 |
| Variance (\( \sigma^2 \)) | 112.5 | 54 |
| Sample Size (\( n \)) | 45 | 36 |
Refer to Exhibit GGC 2-2. The test statistic for the difference between the two population means is ____.
**Options:**
- a) \(-.47\)
- b) \(-.65\)
- c) \(-3\)
- d) \(-1.5\)
### Explanation
To find the test statistic for the differences between the two means, use the formula for the two-sample Z-test:
\[
Z = \frac{(\bar{x}_1 - \bar{x}_2)}{\sqrt{\frac{\sigma_1^2}{n_1} + \frac{\sigma_2^2}{n_2}}}
\]
Where:
- \( \bar{x}_1 \) and \( \bar{x}_2 \) are the sample means
- \( \sigma_1^2 \) and \( \sigma_2^2 \) are the sample variances
- \( n_1 \) and \( n_2 \) are the sample sizes
Substitute in the given values to calculate the Z value and select the correct option.
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