In hilly areas, farmers often contour their fields to reduce the erosion due to water flow. this might have the unintended effect of changing the yield since the rows may not be aligned in an east-west direction to take advantage of direct sunlight.

the following summary statistics show the yields in hundreds of bushels per acre of randomly selected plots of land along hillsides as well as level plots of land nearby with similar soil characteristics.

quartiles

type minimum 10% 25% median 75% 90% maximum
hilly 10.9 10.9 13.3 29.2 58.1 97.4 100%
level 10.9 11.2 18.5 39.3 61.5 103.4 118

means and standard deviations

type number mean standard deviation standard error of mean
hilly 12 39.7 30.4 8.8
level 12 44.6 31.1 9.0

a) describe and compare the distributions.
b) based on your plots, what can you conclude about the types of land.