An experiment was conducted to estimate if there is a difference in the mean growth rate of

Question:

An experiment was conducted to estimate if there is a difference in the mean growth rate of grass based on four brands of fertilizer and whether the conditions are full sun or shade. A randomized block design was used to randomly assign the different fertilizers to two parcels of grass, one in the sun and one in the shade. The growth rate after two weeks (in centimeters) is provided in Table 12.9.

a. Which is the row factor and which is the column factor?

b. How many levels are there for each factor?

c. How many replicates are in each cell?

d. Using Minitab, determine if there is a difference in the mean growth rate based on the brand of fertilizer and whether the grass was in full sun or in the shade.

e. Is there an interaction between the brand of fertilizer and whether the grass was in the sun or the shade?

f. Create a main effects plot and an interaction plot and comment on whether these plots support your findings.
g. Check any relevant model assumptions and describe any violations that you see.

Table 12.9