The purpose of this experiment is to determine the effect of salt in the soil on the emergence of grass seeds. There are three replications of four plots, each treated to contain 0, 8, 16, and 24%...

The purpose of this experiment is to determine the effect of salt in the soil on the emergence of grass seeds. There are three replications of four plots, each treated to contain 0, 8, 16, and 24% salt. The percent of seeds emerging is observed 5, 8, 11, and 14 days after planting. The data are shown in Table 10.29.

There are 12 separate plots; that is, the three replications within each level of salt are unrelated. Within each plot, there are four repeated measurements corresponding to days after planting.

(a) Construct a profile plot that will illustrate the effect of SALT and DAY.

(b) Conduct formal hypothesis tests for SALT, and a SALTTDAY interaction.

(c) Use the profile plot to interpret the results of the hypothesis tests.