The Following Table Shows the Mileage for Four Different Cars

question 6

Essay

The following table shows the mileage for four different cars and three different brands of gas. Assuming no
effect from the interaction between car and brand of gas, test the claim that the four cars have the same mean
mileage. Use a 0.05 significance level. $\begin{array}{l|lll} & \text { Brand 1 } & \text { Brand 2 } & \text { Brand 3 } \\\hline \text { Car 1 } & 22.4 & 25.2 & 24.3 \\\text { Car 2 } & 19 & 18.6 & 19.8 \\\text { Car 3 } & 24.6 & 25 & 25.4 \\\text { Car 4 } & 23.5 & 23.6 & 24.1\end{array}$

$$\begin{array} { l r c r r c } \text { Source } & \text { DF } & \text { SS } & \text { MS } & \text { F } & \text { p } \\\text { Car } & 3 & 61.249 & 20.416 & 39.033 & 0.000249 \\\text { Gas } & 2 & 2.222 & 1.111 & 2.124 & 0.200726 \\\text { Error } & 6 & 3.138 & 0.523 & & \\\text { Total } & 11 & 66.609 & & &\end{array}$$

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Definitions:

Variable Manufacturing Overhead

Costs that vary with the level of production output and include expenses such as indirect materials, supplies, and utilities used in manufacturing.

Variable Overhead Efficiency Variance

The difference between the actual variable overhead incurred and the expected variable overhead based on efficient operations.

Variable Overhead

Costs that vary with the level of production or sales, such as utilities or hourly wages, that are not directly tied to a specific product.

Direct Labor-hours

Sum total of hours expended by workers directly active in the manufacturing domain.