### Home > CCA > Chapter 6 > Lesson 6.1.4 > Problem 6-41

Fabienne compared annual grocery bills with the other mothers at her church. She discovered a linear relationship between the total cost (in dollars) of groceries and the number of miles the mother lived from the downtown church. *6-41 HW eTool* (Desmos). Homework Help ✎

Do you think that the association would be positive or negative? Strong or weak?

This is your own thought and opinion. Answers will vary.

Recall the standards for a weak/strong association.The upper boundary for Fabienne’s prediction was modeled by

*g*= 11.27 – 0.14*d*where*g*is the cost of groceries (in thousands of dollars) and*d*is the distance from church (miles). The lower boundary was*g*= 7.67 – 0.14*d*. Estimate the equation of Fabienne’s line of best fit.The

*y*-intercept should be approximately halfway between 11.27 and 7.67. (Find a number that is halfway).*g*= 9.47 − 0.14*d*Interpret the slope of Fabienne’s model in context.

The slope is represented by −0.14 in the equation, but remember that we are working in thousands of dollars, so it would be $140.

What is the slope saying about the cost in relation to the number of miles?Fabienne lives 8 miles from church. Her residual was $510. About how much did she spend on groceries this year?

Substitute 8 in for

*d*and evaluate.

Your answer is the theoretical amount that Fabienne should pay.

Add the residual of 510 to find the actual amount that she is paying.

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