Question

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.

Manufacturer
	1	2	3
	20	30	23
	26	28	22
	24	33	26
	22	29	25

a. Use these data to test whether the population mean times for mixing a batch of material differ for the three manufacturers. Use .

Compute the values below (to 2 decimals, if necessary).

Sum of Squares, Treatment
Sum of Squares, Error
Mean Squares, Treatment
Mean Squares, Error

Calculate the value of the test statistic (to 2 decimals).

b. At the  level of significance, use Fisher's LSD procedure to test for the equality of the means for manufacturers  and .

Calculate Fisher's LSD Value (to 2 decimals).

Answer 1

a)

sum of square; treatment=	114.67
sum of square; error=	44.00
mean square; treatment=	57.33
mean square; error=	4.89

test statistic =

11.73

b)( please reply if level of significance is different from 0.05 , as it is not specified above)

Fisher's (LSD) for group i and j =                  (tN-k)*(sp*√(1/ni+1/nj)           =

3.54