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## Main Question or Discussion Point

Concrete road pavement gains strength over time as it cures. Highway builders use regression lines to predict the strength after 28 days (when curving is complete) from measurements made after 7 days. Let x be strenth after 7 days (in pounds per square inch) and y the strength after 28 days.

y-hat = 1389 + .96x

Draw a graph of this line, with x running from 3000 to 4000 lbs per square inch.

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I don't know how to graph it because the words are confusing me . . . I labed my explanatory (x-axis) as psi from 3000 to 4000 lbs and the response variable (y-axis) as days. How do I graph 1389 (the intercept) on my graph if the y-axis is days?

y-hat = 1389 + .96x

Draw a graph of this line, with x running from 3000 to 4000 lbs per square inch.

-----------------------

I don't know how to graph it because the words are confusing me . . . I labed my explanatory (x-axis) as psi from 3000 to 4000 lbs and the response variable (y-axis) as days. How do I graph 1389 (the intercept) on my graph if the y-axis is days?