A researcher wishes to study how the average weight Y (in kilograms) of children

Question

A researcher wishes to study how the average weight Y (in kilograms) of children changes during the first year of life. He plots these averages versus the age X (in months) and decides to fit a least-squares regression line to the data with X as the explanatory variable and Y as the response variable. He computes the following quantities. r = correlation between X and Y = 0.9 J = mean of the values of X = 6.5 M = mean of the values of Y = 6.6 sJ = standard deviation of the values of X = 3.6 sM = standard deviation of the values of Y = 1.2 Find the slope of the least-squares line.

Explain it step by step

Explanation / Answer

slope = r*sj/sm = 0.9*1.2/3.6=0.3

This is by standard formula of slope

Intercept= M-slope*J = 6.6-0.3*6.5=4.65

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