A chemist wishes to test the effect of four chemical agents

A chemist wishes to test the effect of four chemical agents on the strength of a particular type of cloth. Because there might be variability from one bolt to another, the chemist decides to use a randomized block design with bolts of cloth considered as blocks. She selects five bolts and applies all four chemicals in random order to each bolt. The resulting tensile strengths follow. Analyze the data from this experiment (use a= 0. 05) and draw appropriate conclusion. Suppose that the observation for chemical type 2 and bolt 3 is missing. Please estimate the missing data.

Solution

Source DF SS MS F P
chemical 3 12.95 4.3167 2.38 0.121
bolt 4 157.00 39.2500 21.61 0.000
Error 12 21.80 1.8167
Total 19 191.75

S = 1.348 R-Sq = 88.63% R-Sq(adj) = 82.00%

under 5% significance we can colclude that the effect of chemical is insignificant where as the effect of bolt much significant