Working hours in four manufacturing plants of the same company seem to differ. Five workers in each plant were randomly selected and asked about their working hours per week. The mean weekly working hours for each of the plants are 49.06, 42.57, 38.25 and 37.91, respectively. An ANOVA F-test revealed that the mean weekly working hours differed across different plants. SOURCE SS df MS F BETWEEN PLANTS 238.17 3 79.39 6.42 WITHIN PLANTS 197.74 16 12.36 TOTAL 435.91 19 Upper management followed this analysis up with multiple comparisons of means using an experiment-wise error rate of 0405. Using Tukey's multiple comparison procedure and assuming that critical value of the range is 4.05, what is the smallest difference that allows you to conclude that two plants have different weekly average working hours? Choose the correct answer below. A. 3.184 O B. 22.385 \f