Why use mann-whitney U test rather than independent sample test?

In summary, the Mann-Whitney U test is preferred over the parametric independent sample test when the data does not meet the assumptions of normality and when the sample sizes are small or there are outliers present.
  • #1
Charles007
22
0
why use non parametric mann-whitney U test rather than parametric independent sample test.

I have a question regarding this because i just complete two question, as one I am using parametric tests, independent sample test, solve the mean selling price of a home with a conservatory different from the mean selling price of a home without conservatory.

I also used non parametric tests, mann-whitney U test , these two test obtain the same result.

can anyone tell me why it's is most appropriate in testing the hypothesis using non-parametric mann-whitney U test?

Thank you very much for your help. I will wait online.
 
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  • #2
Nonparametric tests are useful when the assumptions of parametric tests, such as normality, are not met. The Mann-Whitney U test is a nonparametric alternative to the two-sample t-test and can be used when the data is not normally distributed or when the sample sizes are small. It is also more robust than the t-test when there are outliers present in the data. Additionally, the Mann-Whitney U test does not make any assumptions about the population means or variances, which makes it a better choice for testing the hypothesis when dealing with unknown population characteristics.
 
  • #3


There are several reasons why the Mann-Whitney U test may be more appropriate in testing a hypothesis than the independent sample t-test.

Firstly, the Mann-Whitney U test does not assume that the data follows a specific distribution, whereas the independent sample t-test assumes that the data is normally distributed. This means that the Mann-Whitney U test can be used for data that is not normally distributed, making it a more versatile test.

Secondly, the Mann-Whitney U test is more robust to outliers and extreme values in the data. This means that the results of the test will not be heavily influenced by these values, making it a more reliable test in situations where outliers may be present.

Additionally, the Mann-Whitney U test does not require the assumption of equal variances between the two groups, whereas the independent sample t-test does. This means that the Mann-Whitney U test can be used when the variances of the two groups are not equal, making it a more flexible test.

Finally, the Mann-Whitney U test is non-parametric, meaning that it does not make any assumptions about the underlying population parameters. This makes it a more robust test in situations where the assumptions of parametric tests may not be met.

Overall, the Mann-Whitney U test is a more appropriate choice when the data does not meet the assumptions of the independent sample t-test or when the data is not normally distributed. It is a reliable and versatile test that can provide accurate results in a variety of scenarios.
 

1. Why is the Mann-Whitney U test preferred over the independent sample test?

The Mann-Whitney U test is preferred over the independent sample test because it does not assume that the data follows a normal distribution. This makes it more robust and suitable for non-parametric data, which is common in scientific research. Additionally, the Mann-Whitney U test can handle unequal sample sizes and is more powerful in detecting differences between groups.

2. Can the Mann-Whitney U test be used for both continuous and categorical data?

Yes, the Mann-Whitney U test can be used for both continuous and categorical data, as long as the data is rank-ordered. This means that the data can be put in order from lowest to highest, regardless of the type of data. This makes the test very versatile and applicable to a wide range of research studies.

3. What is the main assumption of the independent sample test?

The main assumption of the independent sample test is that the data follows a normal distribution. This means that the data is symmetrical and bell-shaped when plotted on a graph. If this assumption is violated, the results of the test may not be accurate and could lead to incorrect conclusions.

4. How is the Mann-Whitney U test different from the Wilcoxon rank-sum test?

The Mann-Whitney U test and the Wilcoxon rank-sum test are essentially the same test, but with different names. The Mann-Whitney U test is typically used when comparing two independent groups, while the Wilcoxon rank-sum test is used when comparing two related or paired groups. However, both tests use the same calculation and provide the same results.

5. When should the Mann-Whitney U test be used instead of the t-test?

The Mann-Whitney U test should be used instead of the t-test when the data does not meet the assumptions of the t-test, such as normality or equal variances between groups. It is also more appropriate for non-parametric data or data with outliers. Additionally, the Mann-Whitney U test can handle unequal sample sizes, making it a more versatile option for different research studies.

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