Four different types of solar energy collectors were tested. Each was tested at five randomly chosen times, and the power (in watts) was measured. The results were as follows: Collector Power
A 1.9 1.6 2.0 1.8 1.6
B 1.7 1.9 1.8 1.7 1.7
C 1.2 0.9 1.2 0.9 1.4
D 1.5 1.0 1.4 1.3 1.4
a) If possible, check the assumptions of the ANOVA model for this problem. If not possible, state why.
b) Plot boxplots of the power generated by different collectors. Comment on the results.
c) Estimate mean power of collector C using a 95% confidence interval.
d) Does the mean power differ for different collectors? Please state appropriate hypotheses
e) If the mean power differs for different collectors, which collector types are different from each other? Justify your answer by providing appropriate confidence intervals. Use simultaneous confidence level of 95%.