{"id":200695,"date":"2023-11-07T04:46:17","date_gmt":"2023-11-07T04:46:17","guid":{"rendered":"https:\/\/namso-gen.co\/blog\/how-to-calculate-p-value-for-mann-whitney-test\/"},"modified":"2023-11-07T04:46:17","modified_gmt":"2023-11-07T04:46:17","slug":"how-to-calculate-p-value-for-mann-whitney-test","status":"publish","type":"post","link":"https:\/\/namso-gen.co\/blog\/how-to-calculate-p-value-for-mann-whitney-test\/","title":{"rendered":"How to calculate p value for Mann-Whitney test?"},"content":{"rendered":"

The Mann-Whitney test, also known as the Mann-Whitney U test, is a non-parametric test used to compare two independent groups when the dependent variable is ordinal or continuous, but not normally distributed. The p value for a Mann-Whitney test is a measure of the probability that the observed data would occur if the null hypothesis were true. A significant p value (usually less than 0.05) indicates that the two groups are different.<\/p>\n

To calculate the p value for a Mann-Whitney test, you can use statistical software such as SPSS, R, or even online calculators. The software will generate the p value based on the U statistic obtained from the test. Alternatively, you can calculate the p value manually using the U statistic and the sample size of the two groups.<\/b><\/p>\n

Here is how to calculate the p value manually for a Mann-Whitney test:
\n1. Rank all the data from both groups together in ascending order, assigning ranks to ties by averaging the ranks.
\n2. Calculate the U statistic for each group using the formula:
\n U = n1 * n2 + (n1 * (n1 + 1)) \/ 2 – sum of ranks in group 1
\n where n1 and n2 are the sample sizes of the two groups.
\n3. Determine the smaller of the two U statistics as U.
\n4. Calculate the expected U value if the null hypothesis were true using the formula:
\n Expected U = n1 * n2 \/ 2
\n5. Calculate the z statistic using the formula:
\n z = (U – Expected U) \/ \u221a(n1 * n2 * (n1 + n2 + 1) \/ 12)
\n6. Obtain the p value from the z statistic using a standard normal distribution table or statistical software.<\/p>\n

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