Fertilizers have been the subject of very aggressive advertising recently. To see if they serve their designed purpose, two different fertilizers (A and B) were applied to nine different types of plants. The growth rate in inches per 30 days for each type of plant is recorded below. We would like to determine if fertilizer A is better for growth than fertilizer B

A B

7 5

6 5

5 6

7 6

4 5

8 7

6 6

7 4

a. At the 1% significance level, what would you conclude? (7 marks)

b. What are the limitations on your conclusion to part (a) of this question? Make your explanation in the context of this question. (2 marks)