Answer:
The equation of the linear function that best fits the data is,
<em>y</em> = 18.66<em>x</em> + 66.87.
Step-by-step explanation:
The line of best is of the form: <em>y</em> = <em>mx</em> + <em>b</em>.
Here, <em>m</em> = slope of the line and <em>b</em> = intercept.
The formula to compute the intercept and slope are:
![b=\frac{\sum Y.\sum X^{2}-\sum X.\sum XY}{n.\sum X^{2}-(\sum X)^{2}}](https://tex.z-dn.net/?f=b%3D%5Cfrac%7B%5Csum%20Y.%5Csum%20X%5E%7B2%7D-%5Csum%20X.%5Csum%20XY%7D%7Bn.%5Csum%20X%5E%7B2%7D-%28%5Csum%20X%29%5E%7B2%7D%7D)
![m=\frac{n.\sum XY-\sum X.\sum Y}{n.\sum X^{2}-(\sum X)^{2}}](https://tex.z-dn.net/?f=m%3D%5Cfrac%7Bn.%5Csum%20XY-%5Csum%20X.%5Csum%20Y%7D%7Bn.%5Csum%20X%5E%7B2%7D-%28%5Csum%20X%29%5E%7B2%7D%7D)
Consider the table below for the values of <em>∑ X, ∑ Y, ∑ X² </em>and <em>∑ XY</em>.
Compute the value of intercept and slope as follows:
![b=\frac{\sum Y.\sum X^{2}-\sum X.\sum XY}{n.\sum X^{2}-(\sum X)^{2}}=\frac{(793\times91)-(21\times3102)}{(6\times91)-(21)^{2}} =66.867](https://tex.z-dn.net/?f=b%3D%5Cfrac%7B%5Csum%20Y.%5Csum%20X%5E%7B2%7D-%5Csum%20X.%5Csum%20XY%7D%7Bn.%5Csum%20X%5E%7B2%7D-%28%5Csum%20X%29%5E%7B2%7D%7D%3D%5Cfrac%7B%28793%5Ctimes91%29-%2821%5Ctimes3102%29%7D%7B%286%5Ctimes91%29-%2821%29%5E%7B2%7D%7D%20%3D66.867)
![m=\frac{n.\sum XY-\sum X.\sum Y}{n.\sum X^{2}-(\sum X)^{2}}=\frac{(6\times3102)-(21\times793)}{(6\times91)- (21)^{2}} =18.657](https://tex.z-dn.net/?f=m%3D%5Cfrac%7Bn.%5Csum%20XY-%5Csum%20X.%5Csum%20Y%7D%7Bn.%5Csum%20X%5E%7B2%7D-%28%5Csum%20X%29%5E%7B2%7D%7D%3D%5Cfrac%7B%286%5Ctimes3102%29-%2821%5Ctimes793%29%7D%7B%286%5Ctimes91%29-%20%2821%29%5E%7B2%7D%7D%20%3D18.657)
The line of best fit is:
![y=mx+b\\y=18.657x+66.867\\y=18.66x+66.87](https://tex.z-dn.net/?f=y%3Dmx%2Bb%5C%5Cy%3D18.657x%2B66.867%5C%5Cy%3D18.66x%2B66.87)
Thus, the equation of the linear function that best fits the data is <em>y</em> = 18.66<em>x</em> + 66.87.