Chapter 13, Problem 72H

Sanjay made identical paper airplanes out of three different weights of paper, light, medium and heavy. He made four airplanes from each of the weights, and launched them himself across the room. Here are the distances (in meters) that his planes flew.

Paper Type/Trial	Trial 1	Trial 2	Trial 3	Trial 4
Heavy	5.1 meters	3.1 meters	4.7 meters	5.3 meters
Medium	4 meters	3.5 meters	4.5 meters	6.1 meters
Light	3.1 meters	3.3 meters	2.1 meters	1.9 meters

Table 13.28

Figure 13.8

a. Take a look at the data in the graph. Look at the spread of data for each group (light, medium, heavy). Does it seem reasonable to assume a normal distribution with the same variance for each group? Yes or No.

b. Why is this a balanced design?

c. Calculate the sample mean and sample standard deviation for each group.

d. Does the weight of the paper have an effect on how far the plane will travel? Use a 1% level of significance.

Complete the test using the method shown in the bean plant example in Example 13.4.

• variance of the group means __________

MSbetween= ___________

mean of the three sample variances ___________

MSwithin = _____________

F statistic = ____________

df(num) = __________, df(denom) = ___________

number of groups _______

number of observations _______

p-value = __________ (P(F > _______) = __________)

Graph the p-value.

decision: _______________________

conclusion: _______________________________________________________________