In a study of the nutritional requirements of cattle, researchers measured the weight gains of cows during a 78-day period. For two breeds of cows, Hereford (HH) and Brown Swiss /Hereford (SH), the results are summarized as follows. Assume α =0.10. Assume both populations are normally distributed. HH SH S
n 12 15 9.8
у 20.1 12.4 14.2
Use two-tailed hypothesis testing to see whether the Hereford cows gained similar weight as the Brown Swiss/Hereford cows.
Soil respiration is a measure of microbial activity in soil, which affects plant growth. In one study, soil cores were taken from two locations in a forest: (1) Under an opening in the forest canopy (Gap) and (2) at a nearby area under heavy tree growth (Growth). The soil respiration data are shown below. Assume a =0.10.
Growth Gap
15, 20, 171, 311 30, 11, 16, 15
20, 190, 62 19, 14, 8
Use Wilcoxon-Mann-Whitney test to determine whether soil respiration rate in growth area is different than that in gap area.