1. What is the statistical significance value between numerical exam results from years 2006 and 2004 according to Mann-Whitney U test and data in the attached file?
2. During which year was the mean exam result higher?
3. Is such difference enough for scientifical inference about the level of teaching or the abilities of students in these years?
4. Add the software name you used as different software packages use different algorithms. U test orders the input data by values and equal values in ordered series can be treated differently.

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.

1. How significant (numerically) is the difference between covcerage of coniferous (okasmets) and deciduous (lehtmets) forest according to U testi and attached data? Land cover categories are in the column Maakate/cover.
2. Which of these groups has higher mean coverage?
3. Why the t test is not proper for comparing forest coverage values estimated as percentages?
4. Add the software name you used.