In 1976, there was some question regarding the effectiveness of the noise-silencing in air pollution filters for the cars produced through Associated Octel Company. These data are from a report led in response to this question with Air and Water Pollution Subcommittee of Senate Public Works Committee (data accessible from the Data and Story Library). In the table which is given below the means are given followed by the standard deviation (in parentheses). Is there any evidence that the noise produced (measured in dB) depends on the size of the car used? There were 12 cars in each group.
Small Medium Large
824.167 833.75 772.5
(7.638) (13.51) (10.34)
(a) What are the factor and its levels?
(b) Make the ANOVA table.
(c) Find out the critical F value from the table.
(d) Make the conclusion based upon the information.
(e) Form 94% Bonferroni Simultaneous confidence intervals for the differences. Interpret.
(f) Form 95% confidence intervals using Fisher's technique. Interpret