1 For the data plotted in the scatterplot, ther2value was calculated to be 0.9846.

Which of the following sets of statements is true?

• 98.5% of the variation in yearly income is explained by a nonlinear relationship with age. The correlation coefficient, r, is 0.992.
• 98.5% of the variation in yearly income is explained by a linear relationship with age. The correlation coefficient, r, is 0.992
• 98.5% of the variation in age is explained by a linear relationship with yearly income. The correlation coefficient, r, is 0.969.
• 98.5% of the variation in age is explained by a nonlinear relationship with yearly income. The correlation coefficient, r, is 0.969.

2 For a set of data, x is the explanatory variable.Its mean is 8.2, and its standard deviation is 1.92.

For the same set of data, y is the response variable. Its mean is 13.8, and its standard deviation is 3.03.

The correlation was found to be 0.223.

Select the correct slope and y-intercept for the least-squares line.

• Slope = 0.35 y-intercept = -10.9
• Slope = -0.35 y-intercept = 10.9
• Slope = -0.35 y-intercept = -10.9
• Slope = 0.35 y-intercept = 10.9

3 Which of the following is a guideline for establishing causality?

• Check if the effect is present or absent when the response variable is present or absent.
• Keep all variables the same to get duplicate results.
• Do not consider other possible causes.
• Look for cases where correlation exists between the variables of a scatterplot.