What is a Wilcoxon Sign-Ranked Test (pair t non para)?
-
Upload
ken-plummer -
Category
Education
-
view
94 -
download
0
description
Transcript of What is a Wilcoxon Sign-Ranked Test (pair t non para)?
![Page 1: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/1.jpg)
Wilcoxon Signed-Ranked Test (Paired T)
![Page 2: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/2.jpg)
The Wilcoxon test is the non-parametric analogue to the pair-wise (repeated measures) t-test.
![Page 3: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/3.jpg)
The non-parametric analogue to the pair-wise (repeated measures) t-test is the Wilcoxon test.
You may remember that the pair-wise (repeated measures) t-test is used to determine the statistical significant difference between the same sample/observations or people on two separate occasions.
![Page 4: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/4.jpg)
Here is a simplified data set that would use a paired sample t-test:
![Page 5: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/5.jpg)
Students Pre Post
1 1 7
2 2 6
3 1 8
mean: 1.3 7.0
![Page 6: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/6.jpg)
Students Pre Post
1 1 7
2 2 6
3 1 8
mean: 1.3 7.0
Three students
![Page 7: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/7.jpg)
Students Pre Post
1 1 7
2 2 6
3 1 8
mean: 1.3 7.0
Pre-Quiz
![Page 8: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/8.jpg)
Students Pre Post
1 1 7
2 2 6
3 1 8
mean: 1.3 7.0
Students Receive Instruction
![Page 9: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/9.jpg)
Students Pre Post
1 1 7
2 2 6
3 1 8
mean: 1.3 7.0
Post-Quiz
![Page 10: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/10.jpg)
Students Pre Post
1 1 7
2 2 6
3 1 8
mean: 1.3 7.0
The Mean of the
Pre-quiz
![Page 11: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/11.jpg)
Students Pre Post
1 1 7
2 2 6
3 1 8
mean: 1.3 7.0
The Mean of the
Pre-quizis compared to
![Page 12: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/12.jpg)
Students Pre Post
1 1 7
2 2 6
3 1 8
mean: 1.3 7.0
The Mean of the
Pre-quizis compared to
The Mean of the
Post-quiz
![Page 13: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/13.jpg)
Students Pre Post
1 1 7
2 2 6
3 1 8
mean: 1.3 7.0
The Mean of the
Pre-quizis compared to
The Mean of the
Post-quiz
using a Paired-Sample t-test
![Page 14: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/14.jpg)
It appears that the post-test scores are higher than the pre-test scores. But what is the likelihood of getting this result if we tested one thousand samples of 3.0?
![Page 15: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/15.jpg)
It appears that the post-test scores are higher than the pre-test scores. But what is the likelihood of getting this result if we tested one thousand samples of 3.0?We use the paired-sample t-test to test the likelihood of this result occurring by chance.
![Page 16: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/16.jpg)
It appears that the post-test scores are higher than the pre-test scores. But what is the likelihood of getting this result if we tested one thousand samples of 3.0?We use the paired-sample t-test to test the likelihood of this result occurring by chance.But the Paired-sample t-test can be used when certain assumptions are met:
![Page 17: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/17.jpg)
It appears that the post-test scores are higher than the pre-test scores. But what is the likelihood of getting this result if we tested one thousand samples of 3.0?We use the paired-sample t-test to test the likelihood of this result occurring by chance.But the Paired-sample t-test can be used when certain assumptions are met:1. the data is interval/ratio
![Page 18: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/18.jpg)
It appears that the post-test scores are higher than the pre-test scores. But what is the likelihood of getting this result if we tested one thousand samples of 3.0?We use the paired-sample t-test to test the likelihood of this result occurring by chance.But the Paired-sample t-test can be used when certain assumptions are met:1. the data is interval/ratio2. the data is normally distributed
![Page 19: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/19.jpg)
The Wilcoxon test is appropriate to use when the underlying measurement is on an ordinal scale.
![Page 20: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/20.jpg)
The Wilcoxon test is appropriate to use when the underlying measurement is on an ordinal scale.
3rd Place 15’2”
2nd
Place 16’1”
1st Place 16’3”
![Page 21: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/21.jpg)
3rd Place 15’2”
2nd
Place 16’1”
1st Place 16’3”
The distance between 3rd and 2nd place (11”) is not the same interval as the distance between 2nd and 1st place
(1”)
![Page 22: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/22.jpg)
The Wilcoxon test is appropriate to use when the underlying measurement is on an ordinal scale or the distribution of a dependent variable is highly skewed.
![Page 23: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/23.jpg)
The Wilcoxon test is appropriate to use when the underlying measurement is on an ordinal scale or the distribution of a dependent variable is highly skewed.
![Page 24: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/24.jpg)
The Wilcoxon test is appropriate to use when the underlying measurement is on an ordinal scale or the distribution of a dependent variable is highly skewed.
Like the Paired Sample t-test, the Wilcoxon test will compare whether there are significant differences between the distributions between time-one and time-two.
![Page 25: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/25.jpg)
Time 1 for Distribution A Time 2 for Distribution A
0 0
![Page 26: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/26.jpg)
A Paired Sample t-test would be used if the distributions were more normal and the data were interval or ratio.
![Page 27: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/27.jpg)
A Paired Sample t-test would be used if the distributions were more normal and the data were interval or ratio.
Interval/Ratio scales • assume quantity of the attribute.• have equal intervals.
![Page 28: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/28.jpg)
The Wilcoxon like all nonparametric tests
![Page 29: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/29.jpg)
The Wilcoxon like all nonparametric tests 1. is not sensitive to outliers and therefore is more
appropriate to use when the data is skewed.
![Page 30: What is a Wilcoxon Sign-Ranked Test (pair t non para)?](https://reader035.fdocuments.us/reader035/viewer/2022062616/5495bb50b47959c82f8b4591/html5/thumbnails/30.jpg)
The Wilcoxon like all nonparametric tests 1. is not sensitive to outliers and therefore is more
appropriate to use when the data is skewed.2. (uses the Median instead of the Mean and is
therefore more appropriate to use when the data is rank order or ordinal.