### Home > GB8I > Chapter 4 Unit 5 > Lesson INT1: 4.1.4 > Problem 4-42

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. 4-42 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

, whereis the cost of groceries (in thousands of dollars) andis the distance from church (miles). The lower boundary was. Estimate the equation of Fabienne’s line of best fit.The

*y*-intercept should be approximately halfway betweenand .

(Find a number that is halfway).Interpret the slope of Fabienne’s model in context.

The slope is represented by

in the equation, but remember that we are working in thousands of dollars, so it would be .

What is the slope saying about the cost in relation to the number of miles?Fabienne lives

miles from church. Her residual was . About how much did she spend on groceries this year?

Substitute

in for and evaluate.

Your answer is the theoretical amount that Fabienne should pay.

Add the residual ofto find the actual amount that she is paying.

Use the eTool below to solve the problem.

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