Stat tests

Question 1

When would you use a chi squared test?

Answer 1

If you are comparing frequenices to see if they are significantly different.

E.g. to test the hypothesis that a range of new gm varieties of wheat produce more seeds per seed head than a traditional variety

Question 2

When would you use the t-test?

Answer 2

When you are comparing two means (where the data has been measured) to see if they are statistically different.

E.g. testing the hypothesis that the mean mass of lobsters is higher in areas where collection is band

Question 3

When would you use the spearman’s rank?

Answer 3

To see if there is a consistent change in the value of one variable as another variable increases or decreases.

e.g. to test the hypothesis crop yield increases as fertiliser application increases

Question 4

When would you use a Mann Whitney U test?

Answer 4

To see if there is a significant difference between two means, but the data was calculated or counted.

E.g. to test the hypothesis fewer cars use a road when road charging is introduced