A Researcher Wanted to Examine If Soil Type Had Any

Essay

A researcher wanted to examine if soil type had any effects on the heights of daylilies (Y). The thickness of the soil (X) in the pot was used as the covariate X. Given the data that follow, where there are three types of soil (n = 10 in each group), (a) calculate the adjusted mean values assuming that b_w = 0.5, and (b) determine what effects the adjustment had on the posttest results.
$\begin{array}{ccc}\hline \text { soil type } & \text { heights of daylilies }(Y) & \text { thickness of soil } \\\hline 1 & \bar{Y}_{.1}=20 & \bar{X}_{.1}=21 \\2 & \bar{Y}_{.2}=25 & \bar{X}_{.2}=18 \\3 & \bar{Y}_{3}=30 & \bar{X}_{.3}=15 \\\hline\end{array}$