To test whether the mean time needed to mix a batch of material is the same for machines produced by three manufacturers, the Jacobs Chemical Company obtained the following data on the time (in minutes) needed to mix the material.
a. Use these data to test whether the population mean times for mixing a batch of material differ for the three manufacturers. Use α = .05.
b. At the α = .05 level of significance, use Fisher’s LSD procedure to test for the equality of the means for manufacturers 1 and 3. What conclusion can you draw after carrying out this test?