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 = 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 = 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 LSD approach to determine which shifts have different means.

Using a significance level : F(0.05, 2, 4) = 6.944272, t (0.025, 4) ( = 2.7765)

Solution Q1 :

Block Shift 1 Shift 2 Shift 3

Hourly 48 54 60

Non supervisory 31 36 55

Supervisors/Managers 25 33 40

ANOVA

Source of Variation SS df MS F P - value F - crit

Rows (blocks) 0.006763 6.944272

Columns (Shifts) 0.01527 6.944272

Error

Total

Contrast Absolute Mean Difference LSD Significant ? Conclusion

Shift1 v. Shift2

Shift1 v. Shift3

Shift2 v. Shift3

Question 2

A company has a monthly time series that regularly shows sales being higher in the summer months. This is an

example of which component?

A. Cyclical B. Trend C. Seasonal D. Random

2

Which of the following is true about index numbers? Index numbers are:

A. used to measure the

cyclical component.

B. used to make a relative

comparison of different

time periods.

C. used to measure the

seasonal component.

D. used to measure the trend

component.

3

Assume that the year 2000 is used as the index base period and that sales were 12 million in the year 2000. If

sales were 18 million in the year 2006, the simple index number for the year 2006 is:

A. 6 million B. 150 C. 1.5 D. 0.666

4

The number of future periods covered by a forecast

A. Forecasting Horizon B. Forecasting Period C. Forecasting Interval D. index number

5

changes in time-series data that are unpredictable

A. A random component B. A cyclical component C. A seasonal component D. index number