Here are some examples of when you might use a Mann-Whitney U test: It is considered to be the nonparametric equivalent to the two-sample independent t-test. Smith’s class.A Mann-Whitney U test (sometimes called the Wilcoxon rank-sum test) is used to compare the differences between two independent samples when the sample distributions are not normally distributed and the sample sizes are small (n <30). Howard’s class had significantly larger test scores than Dr. Because we know that the difference between these two classes were significant, we can now say that Dr. Howard’s class had a mean of 88.5, whereas Dr. To figure this out, we need to look at the descriptive statistics in the second table. But, from this, we cannot tell which class had higher test scores. This means that our results are statistically significant, and there is a significant difference between the test scores of Dr. To interpret these results, we should look at the p-value listed in the first table. Now that we have our descriptive statistics, your results should look like the following:ĭo your results look like this? If so, great! If not, go back and see where your results differed from my instructions. To obtain our descriptive statistics, we just click the box beside “Descriptives”. To do so, we want to click on Class and the click on the right-facing arrow next to the “Grouping Variable” box.Īs you will see, Jamovi will then automatically calculate our results however, there is another piece of information that we need before we should look at our results – the descriptive statistics. Then, we want to designate Class as our grouping variable in Jamovi. To do so, we want to click on Test Grades and then click on the right-facing arrow next to the “Dependent Variables” box. To conduct our analyses, we want to designate Test Grades as our outcome variable in Jamovi. Now click on “Independent Samples T-Test”. To start, click on the “T-Tests” button at the top of the window. The data should look something like this: Click on the link above each picture to view a larger version of the picture in a new window. Also, the pictures below are a little small on the page. csv file, which Jamovi can open, please click here. xls format, but Jamovi cannot open this format. Smith) to determine which class has higher grades on an exam.Īlso, this file is in. In the example dataset, we are comparing the test grades of two classes (Dr. If you don’t have a dataset, download the example dataset here. Now that we know what a two-sample t-test is used for, we can now calculate a two-sample t-test in Jamovi! To begin, open your data in Jamovi.
0 Comments
Leave a Reply. |