Question

The following data refer to tomato yields for 4 different salinity levels:

Salinity	Yield
1.6	59.5	53.3	56.8	63.1	58.7	54.7
3.8	55.2	59.1	52.8	54.5	53.1
6.0	51.7	48.8	53.9	49.0	52.0
10.2	44.6	48.5	41.0	47.3	46.1	48.3

Do the data provide sufficient evidence to conclude that the distribution of yields differs by salinity?

Use a 10% level of significance (Populations are not normally distributed, use Kruskall-Wallis H-test).

Answer 1

Kruskal-Wallis Test: Yield versus Salinity

Kruskal-Wallis Test on Yield

Salinity N Median Ave Rank Z
1.6 6 57.75 18.2 2.95
3.8 5 54.50 15.0 1.37
6.0 5 51.70 9.6 -0.74
10.2 6 46.70 3.5 -3.54
Overall 22 11.5

H = 17.31 DF = 3 P = 0.001

Since p-value<0.1 so we conclude that the data provide sufficient evidence that the distribution of yields differs by salinity.