# Least Square Regression

A doctor wanted to determine whether there is a relation between a

male's age and his HDL (so called good) cholesterol. He randomly selected 17 of his patients and determined their cholesterol.

a. Determine the least-squares regression equation from the sample

data.

b. Compute the standard error of y'

c. Compute the standard error of the slope "b" (note y' = a + bx)

d.Construct a 95% confidence interval about the slope.

e. Suppose a 42 year old man vists the doctor's office. What would be a good guess as to the HDL cholesterol of this patient?

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#### Solution Preview

a) Assume the least-squares regression equation is Y = b X + a, we can use the formula:

Let x=X-mean(X) and y=Y-mean(Y) and mean(X)=45, mean(Y)= 44.94

b = SUM(x*y)/SUM(x^2) = ...

#### Solution Summary

The solution discusses A doctor wanted to determine whether there is a relation between a

male's age and his HDL (so called good) cholesterol. He randomly selected 17 of his patients and determined their cholesterol.