CB Industries operates three shifts every day of the week. Each shift includes full-time hourly workers, nonsupervisory salaried employees, and supervisors/ managers. CB Industries would like to know if there is a difference among the shifts in terms of the number of hours of work missed due to employee illness. To control for differences that might exist across employee groups, CB Industries randomly selects one employee from each employee group and shift and records the number of hours missed for one year. The results of the study are shown here:
a. Develop the appropriate test to determine whether blocking is effective or not. Conduct the test at the $\alpha=0.05$ level of significance.
b. Develop the appropriate test to determine whether there are differences in the average number of hours missed due to illness across the three shifts. Conduct the test at the $\alpha=0.05$ level of significance.
c. If it is determined that a difference in the average hours of work missed due to illness is not the same for the three shifts, use the $L S D$ approach to determine which shifts have different means.