Question: 2.8. A comparison was made of the efficiency of four different unit-dose injection systems. A group of pharmacists and nurses were the "blocks." For each system, they were to remove the unit from its outer package, assemble it, and simulate an injection. In addition to the standard system of using a disposable syringe and needle to draw the medication from a vial, the other systems tested were Vari-Ject (CIBA Pharmaceutical), Unimatic (Squibb), and Tubex (Wyeth). Listed in the following table are the average times (in seconds) needed to implement each of the systems (153).

(a) Test the equality of the means at the 0.05 level.

(b) Use Tukey's method to test all six pairwise differences of the four 'kis. Let a = 0.05.

Note: SSTOT = 2056.10, SSTR = 1709.60, and SSB = 193.53; Q.05,4.27 = 4.34.