Question

Lab 12-Stat 212 Online Suppose we have the following scenario: Rapid drainage of floodwater is crucial to prevent damage during heavy rains. Several designs for a drainage canal were considered for a certain city. Each design was tested four times, to determine how long it took to drain the water in a reservoir. The following table presents the drainage times, in minutes. Mean S. Dev. Variance (ie. SD) n The overall average is x = 39.67 Type 1 44 4.12 16.99 Type 2 44.1 6.57 43.15 4 Type 3 30.9 5.67 32.17 4 a. Calculate the "Within" variance, sm, by averaging the category variances (i.e. take the average of the 3 numbers in the Variance line in the table above). b. Calculate s by calculating the variance between the sample means Type Type mean Type mean - overall mean (subtract the overall mean of 39.67 from each of the type means) (Type mean - overall mean) Type 1 44 Type 2 44.1 Type 3 30.9 Total The value sê is the total from the shaded box divided by the number of types (categories) minus 1. In this case, we will divide by 2. c. Determine the "Between" Variance, sę, by multiplying the answer from part b, s, by the number of observations in each sample. i.e. s; = ns d. Calculate the F-Statistic by dividing the answer from partc by the answer from part b.

Answer 1