In an experiment on growing sweet peas, a team of students selected 2 factors at 4 levels each and recorded Weight, Stem Length, and Root Length after 6 \ days of growth. They grew plants using various amounts of Water and Quick grow solution, a fertilizer designed to help plants grow faster. Each factor was run at 4 levels: little, some, moderate, and full. They grew 2 plants under each of the 16 conditions.
An interaction plot of Weight in mg (x-axis is Quick growing-levels are water) shows:


Because of this, a two-way ANOVA with interaction model was fit to the data, resulting in the following ANOVA table:


Residuals plots showed no violations of the variance or Normality conditions. A table of effects for Quick grows shows:
Level of Quick Grow
Effect
Little
Some
Moderate
Full
213.8
97.1
-155.5
-155.5
A table of effects for Water shows:
Level of water
Effect
Little
Some
Moderate
Full
-91.1
-81.9
66.4
106.0
Write a report summarizing what the students have le about the effects of Water and Quick grow solution on the early stages of sweet pea growth as measured by Weight