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Calculate the line of best fit using m= y2-y1/x2-x1 using your brain not a calculator

Calculate The Line Of Best Fit Using M Y2y1x2x1 Using Your Brain Not A Calculator class=

Sagot :

Take two points

  • (1,940)
  • (2,950)

Slope

  • m=950-940/2-1=10

Equation in point slope form

  • y-y1=m(x-x1)
  • y-940=10(x-1)
  • y-940=10x-10
  • y=10x-10+940
  • y=10x+930

Answer:

[tex]y=-\dfrac{300}{7}x+1000[/tex]

Step-by-step explanation:

Method 1  (see attachment 1 with red line)

Plots the points on a graph and draw a line of best fit, remembering to ensure the same number of points are above and below the line.

Use the two end-points of the line of best fit to find the slope:

[tex]\textsf{let}\:(x_1,y_1)=(0,1000)[/tex]

[tex]\textsf{let}\:(x_2,y_2)=(7,700)[/tex]

[tex]\textsf{slope}\:(m)=\dfrac{y_2-y_1}{x_2-x_1}=\dfrac{700-1000}{7-0}=-\dfrac{300}{7}[/tex]

Input the found slope and point (0, 1000) into point-slope form of a linear equation to determine the equation of the line of best fit:

[tex]\implies y-y_1=m(x-x_1)[/tex]

[tex]\implies y-1000=-\dfrac{300}{7}(x-0)[/tex]

[tex]\implies y=-\dfrac{300}{7}x+1000[/tex]

Method 2  (see attachment 2 with blue line)

If you aren't able to plot the points, you should be able to see that the general trend is that as x increases, y decreases.  Therefore, take the first and last points in the table and use these to find the slope:

[tex]\textsf{let}\:(x_1,y_1)=(1,940)[/tex]

[tex]\textsf{let}\:(x_2,y_2)=(7,710)[/tex]

[tex]\textsf{slope}\:(m)=\dfrac{y_2-y_1}{x_2-x_1}=\dfrac{710-940}{7-1}=-\dfrac{115}{3}[/tex]

Input the found slope and point (1, 940) into point-slope form of a linear equation to determine the equation of the line of best fit:

[tex]\implies y-y_1=m(x-x_1)[/tex]

[tex]\implies y-940=-\dfrac{115}{3}(x-1)[/tex]

[tex]\implies y=-\dfrac{115}{3}x+\dfrac{2935}{3}[/tex]

View image semsee45
View image semsee45