Physical abilities of students in two groups: runners and of chess players was compared. Heart rate values per minute after exercise were the following.

Runners: 120 95 132 145 180 100 110 115 125 120 125 ja 130

Chess players: 140 170 180 160 160 150 120 110 125 ja 140.

1. How significant is the difference according to the Mann-Whitney U test (giv p value)?Lets assume that the samples represent runners and chess players in general.
2. Why this assumption is added?
3. Why only a sample of bouth group was used?
4. Add sofware name you used.

Copy the heart rate values from the excercise text. These should be prepared as demanded by the package you use.E.g Vassarstats solution expects data in two columns.

Statistica expects grouping codes in one column and values for the dependent variable in other column. Select: Statistics → Nonparametrics → Comparing two independent samples.

In the SDC Difference tests you have options how to prepare the data (joonis). Anyhow, you have to transpose (in Excel) the numbers from a line to a column.

The next questions ask to explai why we couldn’t simply compare the mean values of bouth groups? Why we need the tedious significance calculations at all?