Researchers Wish to Study Fuel Consumption Rates Based on Speed

question 127

Multiple Choice

Researchers wish to study fuel consumption rates based on speed.The data from 10 cars are below. $\begin{array} { | l | l | } \hline \text { Speed } & \text { Miles/Gallon } \\\hline 15 & 14 \\\hline 23 & 17 \\\hline 30 & 20 \\\hline 35 & 24 \\\hline 42 & 26 \\\hline 45 & 23 \\\hline 50 & 18 \\\hline 54 & 15 \\\hline 60 & 11 \\\hline 65 & 10 \\\hline\end{array}$
It can be shown that for these data: $\bar{X}=41.9, \quad \bar{y}=17.8, \quad \sum_{i=1}^{10}\left(x_{i}-\bar{x}\right) ^{2}=2352.9$
$\sum_{i=1}^{10}\left(y_{i}-\bar{y}\right) ^{2}=267.6, \quad \sum_{i=1}^{10}\left(x_{i}-\bar{x}\right) \left(y_{i}-\bar{y}\right) =-270.2$
Calculate the sample correlation coefficient.

• A)0.12
• B)-0.12
• C)-0.36
• D)-0.34
• E)0.34

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Definitions:

Perennial

Describes plants that live for more than two years or streams that flow continuously throughout the year.

Gradient

A rate of inclination or slope, or the rate at which a physical quantity changes with respect to change in another quantity.

Cross-sectional Area

The area of a particular section of an object or material that is exposed when it is cut through by a plane.

Deposition

The geological process by which sediments, soil, and rocks are added to a landform or landmass, often carried by wind, water, or ice.