3.1 - Scatter Plots & Correlation

You have data for many years on the average price of a barrel of oil and the average retail price of a gallon on unleaded regular gasoline. If you want to see how well the price of oil predicts the price of gas, then you should make a scatterplot with __________ as the explanatory variable.

• The price of oil

• the price of gas

• the year

• either oil price or gas price

• time

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CCSS.8.SP.A.1

In a scatterplot of the average price of a barrel of oil and the average retail price of a gallon of gas, you expect to see

• very little association

• a weak negative association

• a strong negative association

• a weak positive association

• a strong positive association

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CCSS.8.SP.A.1

The following graph plots the gas mileage (miles per gallon) of various cars from the same model year versus the weight of these cars in thousands of pounds. The points marked with red dots correspond to cars made in Japan. From this plot, we may conclude that

• there is a positive association between weight and gas mileage for Japanese cars.

• the correlation between weight and gas mileage for all cars is close to 1.

• there is little difference between Japanese cars and cars made in other countries.

• Japanese cars tend to be lighter in weight than other cars

• Japanese cars tend to get worse gas mileage than other cars.

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CCSS.8.SP.A.1

If women always married men who were 2 years older than themselves, what would the correlation between the ages of husband and wife be?

• 2

• 1

• 0.5

• 0

• Can't tell without seeing the data

The figure below is a scatterplot of reading test scores against IQ test scores for 14 fifth-grade children. There is one low outlier in the plot. What effect does this low outlier have on the correlation?

• It makes the correlation closer to 1

• It makes the correlation closer to 0 but still positive

• It makes the correlation closer to 0

• It makes the correlation negative

• It has no effect on the correlation

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CCSS.8.SP.A.1

If we leave out the low outlier, the correlation for the remaining 13 points in the preceding figure is closest to

• -0.95

• -0.5

• 0

• 0.5

• 0.95