An automobile dealer conducted a test to determine if the time in minutes 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 obtained follow.
$$\begin{array}{lcc} & \multicolumn{2}{c} {\text { Analyzer }} \\& \text { Computerized } & \text { Electronic } \\\text { Compact } & 50 & 42 \\\text { Intermediate } & 55 & 44 \\\text { Full-sized } & 63 & 46\end{array}$$
Use $\alpha=.05$ to test for any significant differences.