We are given the following relation:
y = 4.302 x – 3.293
To solve for the mean value of y when x = 20, what we have to do is to find for the value of y at x = 20 and the value of y at x = 0. Then we get the average of the two values.
when x = 0
y(0) = 4.302 (0) – 3.293
y(0) = - 3.293
when x = 20
y(20) = 4.302 (20) – 3.293
y(20) = 82.747
The mean value would be:
mean y = [y(20) + y(0)] / [20 + 0]
mean y = [82.747 + (-3.293)] / 20
mean y = 3.9727 = 3.97