To test whether the mean time needed to mix a batch of material is the same for machines produced ...

     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.                        Use Fisher's LSD procedure to develop a   95% confidence interval estimate of the difference between the means for   manufacturer 1 and manufacturer 2. Round to two decimal places. Enter   negative values as negative numbers.