AP Stats Linear Regression and Correlation Review

Estimate the correlation coefficient from the graph shown.

• r = -0.956

• r = 0.956

• r = -0.438

• r = 0

Which of the following could be true?

• The correlation between a football player's weight and the position he plays is 0.54
• The correlation between the amount of fertilizer used and the yield of beans is 0.42.
• The correlation between a car's length and its fuel efficiency is 0.71 miles per gallon.
• There is a high correlation of 1.09 between height of a corn stalk and its age in weeks.

What is the value of the correlation coefficient, r?

• 0.921
• -0.921
• 0.960
• -0.960

How do you calculate a residual?

• Actual - Predicted

• Predicted - Actual

• Take the square root of R²

• Multiply r by s_y and divide by s_x

The scatter plot shows the relationship between the number of chapters and the total number of pages for several books. The residual for 12 chapters would be ______.

• positive

• negative

• zero

• impossible to determine from this graph

Write the linear regression equation for the data set foot length (x) and height (y).

• y = 28.93 + 1.155x
• height = 28.39(foot length) + 1.155
• y = 1.878 + 117.99x
• height = 117.99 + 1.878(foot length)

Some data was collected on the weight of a hamster for the first 25 weeks after its birth. The linear regression equation is: Weight = 100 + 40(Time). Which is the best description of the slope for this regression equation in context of the problem?

• The slope tells us that hamsters will gain 100 pounds per week.

• The slope is 40 grams/week which means the hamster is predicted to gain weight at this rate.

• The slope is 40 and it means the hamsters are predicted to gain 1 pound every 40 weeks.

• The slope is 100, which is the weight at birth.

Which is the best description of the y-intercept for the linear regression equation for data collected on the sample of hamsters: Weight = 100 + 40(Time)?

• The y-intercept is 100, which means the hamster is predicted to weigh 100 grams at birth.

• The y-intercept is 100, which is where the graph crosses the x-axis.

• 100 is where the data starts on the y-axis.

• The y-intercept is 100, which means the hamster is predicted to gain 100 pounds per week.

Find the slope for the LSRL used to predict the income from the years of education.

• $731.25

• $865.38

• $2193.75

• $2925

The equation c = 75 + 5d is used to calculate the cost based on the gigabytes of data used. The R² for this model is 0.98. Which is the correct interpretation of this value?

• The model correctly predicts 98% of the costs.

• 98% of the variation in the number of gigabytes used can be accounted for by the variation in the cost.

• 98% of the variation in the cost can be accounted for by the variation in the number of gigabytes used.

• 98% of the cost is accounted for by the number of gigabytes used.