A Researcher Wanted to Determine If Using an Octane Booster

Multiple Choice

A researcher wanted to determine if using an octane booster would increase gasoline mileage. A random
sample of seven cars was selected; the cars were driven for two weeks without the booster and two weeks
with the booster.
$$\begin{array} { | l | l | } \hline \text { Miles / Gal Without } & \text { Miles / Gal With } \\\hline 21.2 & 23.8 \\\hline 25.4 & 25.6 \\\hline 20.9 & 22.4 \\\hline 27.6 & 28.3 \\\hline 22.8 & 24.5 \\\hline 27.3 & 28.8 \\\hline 23.4 & 25.2 \\\hline\end{array}$$
-A dietician investigated whether apples turned brown at different rates when exposed to air after being washed in hot water or in cold water. She took 12 random apples and cut each in half. She washed one
Half of each apple in hot water and the other half in cold water, and then put both halves out in a tray. Her
Results (in hours until turning a particular shade of brown) are in the table below. At , did she see a
Difference between the two treatments? $$\begin{array} { | l | c | c | c | } \hline & \text { Hot Water } & \text { Cold Water } & \begin{array} { c } \text { Difference } \\\text { by Apple }\end{array} \\\hline \text { Sample mean } & 6.00 & 5.95 & - 0.05 \\\hline \text { Sample variance } & 2.10 & 2.50 & 0.65 \\\hline\end{array}$$

A) No, because the test value -0.06 is inside the range (-3.05, 3.05) .
B) No, because the test value -0.21 is inside the range (-3.11, 3.11) .
C) No, because the test value -0.21 is inside the range (-3.05, 3.05) .
D) No, because the test value -0.06 is inside the range (-3.11, 3.11) .