An experiment was run to determine whether four specific firing temperatures affect the density of a certain type of brick. A completely randomized experiment led to the following data:

Temperature Density 100 21.8 21.9 21.7 21.6 21.7 125 21.7 21.4 21.5 21.4 150 21.9 21.8 21.8 21.6 21.5 175 21.9 21.7 21.8 21.4

(a) Does the firing temperature affect the density of the bricks? Use ???? = 0.05.

(b) Is it appropriate to compare the means using the Fisher LSD method (for example) in this experiment?

(c) Analyze the residuals from this experiment. Are the analysis of variance assumptions satisfied?

(d) Construct a graphical display of the treatment as described in Section 3.5.3. Does this graph adequately summarize the results of the analysis of variance in part (a)?