Pierce isn't getting enough sleep and suspects it is due to spending too much time on his phone before bed. Over the next several days, he decided to track how much time he spends on his phone, x, and how many hours of sleep he gets, y.

Question

Pierce isn't getting enough sleep and suspects it is due to spending too much time on his phone before bed. Over the next several days, he decided to track how much time he spends on his phone, x, and how many hours of sleep he gets, y.

Hours on the phone before bed Hours of sleep
0.4 9
1.4 4
1.7 8
2.5 5
3.3 4

(4 points)
Use the Desmos graphing calculator (right-click and open on new tab/screen) to calculate the following. Round numbers in the regression line to the nearest thousandths.

r=

y=

x +

Using this regression line, how many hours of sleep would Pierce get if he was on his phone for 5 hours before bed?

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Answer 1

Using the Desmos calculator, the correlation coefficient (r) is approximately -0.888.

The regression line for the data is: y = -1.745x + 9.056.

If Pierce was on his phone for 5 hours before bed, using the regression line, he would be expected to get approximately 0.606 hours of sleep (or about 36 minutes).