Eleven tires were each measured for tread wear by two methods, one based on weight and the other on groove wear. Here are the data (tire_data.txtPreview the document) in thousands of miles:
Weight 30.5 30.9 31.9 30.4 27.3 20.4 24.5 20.9 18.9 13.7 11.4
Groove 28.7 25.9 23.3 23.1 23.7 20.9 16.1 19.9 15.2 11.5 11.2
Does it appear the two methods, on the average, give different results? Set up the hypotheses. Indicate whether you are going to use 2-sample t-test or paired t-test for the problem. If you use 2-sample t-test, will you use pooled or non-pooled variances? What conditions will you check before you perform the test?
Weight Groove
30.5 28.7
30.9 25.9
31.9 23.3
30.4 23.1
27.3 23.7
20.4 20.9
24.5 16.1
20.9 19.9
18.9 15.2
13.7 11.5
11.4 11.2