Question 1075942: Find the equation of the median-median line for the data.
My three points are (500, 524), (2071, 782.5), and (5660, 2330)
Somehow I have come up with the same equation for Line A and Line B, and then again for the median-median line.
y = 0.35x + 349
Am I doing something incorrectly and if so, what is it?
Answer by rothauserc(4718)   (Show Source):
You can put this solution on YOUR website! Label the three points m1, m2, m3 then
:
m1 is (500, 524), m2 is (2071, 782.5) and m3 is (5660, 2330)
:
start with the slope of the line through m1 and m3
:
slope(m1-m3) = (2330 - 524) / (5660 - 500) = 0.35
:
y(m1-m3) = 524 +(0.35)(x-500)
y(m1-m3) = 0.35x +349
:
y(m2) = 782.5 +(0.35)(x-2071)
y(m2) = 0.35x +57.65
:
The median-median line is parallel to y(m1-m3) and y(m2) so it will have the same slope(0.35).
:
To find the y-intercept of the median-median line, we find the mean of the y-intercepts of the lines through M1, M2, and M3. Since there is one line that passes through M1 and M3, the y-intercept for these lines are both 349. The y-intercept of the line through M2 is 57.65.
:
The mean of the y-intercepts is (349 +349 +57.65) / 3 = 251.8833
:
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y(median-median) = 0.35x +251.8833
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