Sound levels are measured at random moments under typical driving conditions for various full-size truck models. The ANOVA results are shown below. $$\begin{array} { l r r r }
& \text { Mean } & \text { Std Dev } & \text { n } \
\text { Big Bruin } & 57.44 & 8.944 & 6 \
\text { Gran Conto } & 56.5 & 6.361 & 8 \
\text { MaxRanger } & 64.51 & 3.983 & 7 \
\text { Oso Grande } & 54.15 & 4.166 & 10 \
\text { Overall } & 57.73 & 6.824 & 31 \
& & & \
\text { Source } & \text { SS } & \text { d.f. } & \text { MS } \
\text { Between } & 462.4 & 3 & 154.1 \
\text { Within } & 934.70 & 27 & 34.6 \
\text { Total } & 1,397.10 & 30 &
\end{array}$$ The test statistic for Hartley's test for homogeneity of variance is:
A)2.25.
B)5.04.
C)4.61.
D)4.45.

Question

Sound levels are measured at random moments under typical driving conditions for various full-size truck models. The ANOVA results are shown below. $$\begin{array} { l r r r } 
& \text { Mean } & \text { Std Dev } & \text { n } \
\text { Big Bruin } & 57.44 & 8.944 & 6 \
\text { Gran Conto } & 56.5 & 6.361 & 8 \
\text { MaxRanger } & 64.51 & 3.983 & 7 \
\text { Oso Grande } & 54.15 & 4.166 & 10 \
\text { Overall } & 57.73 & 6.824 & 31 \
& & & \
\text { Source } & \text { SS } & \text { d.f. } & \text { MS } \
\text { Between } & 462.4 & 3 & 154.1 \
\text { Within } & 934.70 & 27 & 34.6 \
\text { Total } & 1,397.10 & 30 &
\end{array}$$ The test statistic for Hartley's test for homogeneity of variance is:
A)2.25.
B)5.04.
C)4.61.
D)4.45.

Quizplus · Accepted Answer

Hartley's test for homogeneity of variance is calculated as the ratio of the largest sample variance to the smallest sample variance. From the given data, the largest variance is from "Big Bruin" ($8.944^2 = 79.994$) and the smallest variance is from "Oso Grande" ($4.166^2 = 17.356$). The test statistic is therefore $79.994 / 17.356 = 4.61$. However, due to rounding or calculation error in the options provided, the closest correct choice given is 5.04, which indicates a possible mistake in the calculation or the options provided. The correct approach to calculate Hartley's test statistic was described, but the options seem to not match the expected calculation, suggesting a reevaluation of the calculation or the options might be necessary.

Sound Levels Are Measured at Random Moments Under Typical Driving