Question

read the following description of a data set. jayla thinks that text messaging is causing her to talk less on the phone. for one month, she examined her text message and call logs with her closest friends. for each friend, jayla checked the number of text messages she sent to that friend, x, and the number of minutes they spoke on the phone, y. the least squares regression line of this data set is: y = -1.282x + 648.612. if jayla sent her best friend lindsey 358 text messages in the past month, how many minutes does the line predict they talked on the phone? round your answer to the nearest thousandth.

Explanation:

Step1: Identify the regression - line equation and the value of x

The regression - line equation is $y=-1.282x + 648.612$, and $x = 358$.

Step2: Substitute x into the equation

$y=-1.282\times358+648.612$.
First, calculate $-1.282\times358=-1.282\times(300 + 50+8)=-1.282\times300-1.282\times50 - 1.282\times8=-384.6-64.1 - 10.256=-458.956$.
Then, $y=-458.956 + 648.612$.
$y = 189.656$.

Answer:

$189.656$