A linear regression equation is calculated for a sample of n = 20 pairs of X and Y values.

What would be the df value for the standard error of estimate?

A) 19 B) 18 C) 2 D) 1

Answer: B) 18

Step-by-step explanation:

The degree of freedom for Standard error or df (Residual) is the sample size minus the number of estimated parameters,.

df = n - p, where n = sample size, p = number of parameters.

According to the given problem, we have

Sample size : n=20

Number of parameters (x and y) : p = 2

Then, the df value for the standard error of estimate will be:

df = n-p = 20-2=18

Thus, the df value for the standard error of estimate is 18.

Hence, the correct answer is B) 18.