Question

A farmer wants to know the effect of using various amounts of fertilizer in relation to the yield of his crops. He subdivided a portion of his land into 10 separate, but essentially equal, plots. He divided the land so that all of the plots had equal exposure to sun, rain, and other environmental conditions. He randomly selected 2 of the 10 plots and spread 2 pounds of fertilizer over each of them. Then he randomly selected 2 of the remaining plots and spread 3 pounds of fertilizer over each of them. He continued with the last sets of plots in the same manner, spreading 4, then 5, then 6 pounds of fertilizer over each of them. Below is a computer output for linear regression of amount of fertilizer versus yield for the 10 plots of land.

Predictor Coef SE Coef T P
Constant 10.100 0.7973 12.67 0.000
Fertizer 1.50 0.1879 6.12 0.000

S= 0.8404; R-Sq= 82.4% R-Sq(adj) = 80.28%

Required:
What is the equation of the least squares regression line from this sample?

Answer 1

Y = 10.1 + 1.50x

Explanation:

From the data contained in the computer output for linear regression

The coefficient of intercept = 10.1

coefficient of fertilizer = 1.50

Sample of an Equation of least squares regression line

y = a + bx

where : a = intercept , b = slope

hence the required equation will be

Y = 10.1 + 1.50x

y = yield , x = fertilizer