You are the production manager at a parachute manufacturing company. Parachutes are woven in your factory using a synthetic fiber purchased from one of four different suppliers. The strength of these fibers is an important characteristic that ensures quality parachutes. You need to decide whether the synthetic fibers from each of your four suppliers result in parachutes of equal strength. Furthermore, to produce parachutes your factory uses two types of looms, the Jetta and the Turk. You need to determine if the parachutes woven on each type of loom are equally strong. You also want to know if any differences in the strength of the parachute can be attributed to the four suppliers are dependent on the type of loom used. You conduct an experiment in which five different parachutes from each supplier are manufactured on each of the two different looms and collect and store the data in Parachute Two Way.

At the 0.05 level of significance,

a. is there an interaction between supplier and loom?

b. is there an effect due to loom?

c. is there an effect due to supplier?

d. Plot the mean strength for each supplier for each loom.

e. If appropriate, use the Tukey procedure to determine differences between suppliers.

f. Repeat the analysis, using the Parachute one way file with suppliers as the only factor. Compare your results to those of (b) and (e).