Are the alloy means different at the 1% significance level (a = 0.01).  Perform t-test using the sample data and do not assume the standard deviations are equal.  Yes  /  No.

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
icon
Related questions
Question

Are the alloy means different at the 1% significance level (a = 0.01).  Perform t-test using the sample data and do not assume the standard deviations are equal.  Yes  /  No.  Justify answer. 

## Oneway Analysis of Strength By Alloy Type

### Box Plot Explanation
The box plot represents the strength distribution of two alloy types, Alloy B and Alloy A. Each box plot displays the following statistics:
- **Median**: The line inside the box shows the median strength.
- **Quartiles**: The top and bottom of each box represent the 75th percentile (upper quartile) and 25th percentile (lower quartile), respectively.
- **Whiskers**: The lines extending from the top and bottom of each box indicate variability outside the upper and lower quartiles. These whiskers typically represent 1.5 times the interquartile range from the quartiles.
- **Outliers**: Individual points beyond the whiskers indicate potential outliers.

### Quantiles Table
This table provides detailed quantile data for each alloy type:

| Level   | Minimum | 10%   | 25%   | Median | 75%   | 90%   | Maximum |
|---------|---------|-------|-------|--------|-------|-------|---------|
| Alloy B | 8.63    | 9.428 | 10.86 | 12.3   | 13.49 | 15.036| 16.26   |
| Alloy A | 8.77    | 8.818 | 9.5625| 10.515 | 11.3175| 12.015| 12.18   |

### t Test Analysis
This section presents a t-test comparing Alloy A and Alloy B strengths:

- **Assuming unequal variances**
  - **Difference**: -1.7005
  - **Std Err Dif**: 0.5896
  - **t Ratio**: -2.88434
  - **DF**: 22.92358
  - **Upper CL Dif**: -0.0449, Prob > |t| = 0.0084*
  - **Lower CL Dif**: -3.3561, Prob > t = 0.9958
  - **Confidence**: 0.99, Prob < t = 0.0042*

The probabilities marked with an asterisk (*) indicate statistical significance, suggesting a meaningful difference in strength between the two alloys. The t-test graph visually represents the null hypothesis distribution and critical regions.
Transcribed Image Text:## Oneway Analysis of Strength By Alloy Type ### Box Plot Explanation The box plot represents the strength distribution of two alloy types, Alloy B and Alloy A. Each box plot displays the following statistics: - **Median**: The line inside the box shows the median strength. - **Quartiles**: The top and bottom of each box represent the 75th percentile (upper quartile) and 25th percentile (lower quartile), respectively. - **Whiskers**: The lines extending from the top and bottom of each box indicate variability outside the upper and lower quartiles. These whiskers typically represent 1.5 times the interquartile range from the quartiles. - **Outliers**: Individual points beyond the whiskers indicate potential outliers. ### Quantiles Table This table provides detailed quantile data for each alloy type: | Level | Minimum | 10% | 25% | Median | 75% | 90% | Maximum | |---------|---------|-------|-------|--------|-------|-------|---------| | Alloy B | 8.63 | 9.428 | 10.86 | 12.3 | 13.49 | 15.036| 16.26 | | Alloy A | 8.77 | 8.818 | 9.5625| 10.515 | 11.3175| 12.015| 12.18 | ### t Test Analysis This section presents a t-test comparing Alloy A and Alloy B strengths: - **Assuming unequal variances** - **Difference**: -1.7005 - **Std Err Dif**: 0.5896 - **t Ratio**: -2.88434 - **DF**: 22.92358 - **Upper CL Dif**: -0.0449, Prob > |t| = 0.0084* - **Lower CL Dif**: -3.3561, Prob > t = 0.9958 - **Confidence**: 0.99, Prob < t = 0.0042* The probabilities marked with an asterisk (*) indicate statistical significance, suggesting a meaningful difference in strength between the two alloys. The t-test graph visually represents the null hypothesis distribution and critical regions.
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 2 steps

Blurred answer
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
Statistics
ISBN:
9781119256830
Author:
Amos Gilat
Publisher:
John Wiley & Sons Inc
Probability and Statistics for Engineering and th…
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 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…
Elementary Statistics: Picturing the World (7th E…
Statistics
ISBN:
9780134683416
Author:
Ron Larson, Betsy Farber
Publisher:
PEARSON
The Basic Practice of Statistics
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
Introduction to the Practice of Statistics
Statistics
ISBN:
9781319013387
Author:
David S. Moore, George P. McCabe, Bruce A. Craig
Publisher:
W. H. Freeman