22. The following data refers to yield of tomatoes (kg/plot) for four different levels of salinity; salinity level here refers to electrical conductivity (EC), where the chosen levels were EC
1.6, 3.8, 6.0, and 10.2 nmhos/cm:

1.6 59.5 53.3 56.8 63.1 58.7 3.8 55.2 59.1 52.8 54.5 6.0 51.7 48.8 53.9 49.0 10.2 44.6 48.5 41.0 47.3 46.1 Use the F test at level 
.05 to test for any differences in true average yield due to the different salinity levels.