Covariance Matrix, Regression Analysis, Standard Error, Confidence Interval, Hands On Tutorials.
50 and there are 3 regression variables including the intercept. So, (n-k)= 50–3=47. The 2-sided t-value at α=0.05 is 2.012. The 95% confidence interval for the estimate for Curb_Weight’s coefficient would be calculated as follows: 95% CI for Curb_Weight = (-0.009330) +/- (2.012 * 0.002586) =