An automobile dealer conducted a test to determine whether the time needed to complete a minor engine tune-up depends on whether a computerized engine analyzer or an electronic analyzer is used. Because tune-up time varies among compact, intermediate, and full-sized cars, the three types of cars were used as blocks in the experiment. The data (time in minutes) obtained follows. Use a=0.05 to test for any significant differences.
Analyzer Computerized Electronic Car Compact 50 42 Intermediate 55 44 Full Size 63 46