A gas chromatograph is an instrument that measures the amounts of various compounds contained in a sample by separating the various constituents. Because different components are flushed through the system at different rates, chromatographers are able to both measure and distinguish the various constituents of the sample. A counter is placed somewhere along the instrument that records how much material is passing at various times. By looking at the counts at various times, the chemist is able to reconstruct the amounts of various compounds present. The total number of counts is proportional to the amount of the compound present.
An experiment was performed to see whether slowing down the flow rate would increase total counts. A mixture was produced with three different Concentration levels: low, medium, and high. The two Flow Rates used were slow and/art. Each mixture was run 5 times and the total counts recorded each time. Partial box plots for Concentration and Flow Rate show:

A two-way ANOVA with interaction model was run, and the following ANOVA table resulted:

A plot of residuals vs. predicted values showed:

What conclusions about the effect of flow rate do you draw? Do you see any potential problems with the analysis?