Problem 8E
The article "Effect of Granular Subbase Thickness on Airfield Pavement Structural Response" (K. Gopalakrishnan and M. Thompson, Journal of Materials in Civil Engineering, 2008:331342) presents a study of the effect of the subbase thickness (in mm) on the amount of surface deflection caused by aircraft landing on an airport runway. Two landing gears, one simulating a Boeing 747 aircraft, and the other a Boeing 777 aircraft, were trafficked across four test sections of runway. The results are presented in the following table.
Can you conclude that the mean deflection is greater for the Boeing 777?
Problem 8E
The article "Effect of Granular Subbase Thickness on Airfield Pavement Structural Response" (K. Gopalakrishnan and M. Thompson, Journal of Materials in Civil Engineering, 2008:331342) presents a study of the effect of the subbase thickness (in mm) on the amount of surface deflection caused by aircraft landing on an airport runway. Two landing gears, one simulating a Boeing 747 aircraft, and the other a Boeing 777 aircraft, were trafficked across four test sections of runway. The results are presented in the following table.
Can you conclude that the mean deflection is greater for the Boeing 777?
Step by Step Solution
Step 1 of 4
No. of test , n = 4.
Let the significance level
Denote the population mean of the differences by and the standard deviation by . There are only four differences, which is a small sample. If we assume that the population of differences is approximately normal, we can use the Student’s t test
The null and alternate hypotheses are:
and
Lets determine the differences in the values of he paired data:
Boeing 747 
Boeing 777 
Difference D 

Section 
1 
4.01 
4.57 
0.56 
2 
3.87 
4.48 
0.61 

3 
3.72 
4.36 
0.64 

4 
3.76 
4.43 
0.67 