11.63 The Whitefly in British Columbia The whitefly, which causes defoliation of shrubs and trees and a reduction in salable crop yields, has emerged as a pest in British Columbia. In a study to determine factors that affect the life cycle of the whitefly, an experiment was conducted in which white- flies were placed on two different types of plants at three different temperatures. The observation of interest was the total number of eggs laid by caged females under one of the six possible treatment combi- nations. Each treatment combination was run using five cages.

a. What type of experimental design has been used?

b. Do the data provide sufficient evidence to indicate that the effect of temperature on the number of eggs laid is different depending on the type of plant? Use the MINITAB printout to test the appropriate hypothesis.

c. Plot the treatment means for cotton as a function of temperature. Plot the treatment means for cucumber as a function of temperature. Comment on the simi- larity or difference in these two plots.

d. Find the mean number of eggs laid on cotton and cucumber based on 15 observations each. Calculate a 95% confidence interval for the difference in the underlying population means.

Transcribed Image Text:

Plant Temperature 21.1C 25C 27.8C 37 34 46 21 54 32 Cotton 36 40 41 43 42 36 31 16 38 50 59 43 53 53 62 Cucumber 25 31 71 37 69 49 48 51 59