Question: In the following regression, X = weekly pay, Y = income tax withheld, and n = 35 McDonald’s employees. (a) Write the fitted regression equation. (b) State the degrees of freedom for a twotailed test for zero slope, and use Appendix D to find the critical value at α = .05. (c) What is your conclusion about the slope? (d) Interpret the 95 percent confidence limits for the slope. (e) Verify that F = t 2 for the slope. (f) In your own words, describe the fit of this regression.

Std. Error 6.816

Source SS df MS F p-value

Regression 387.6959 1 387.6959 8.35 .0068

Residual 1,533.0614 33 46.4564

Total 1,920.7573 34

Regression output

confidence interval

variables coefficients std. error t (df

= 33) p-value 95% lower 95% upper

Intercept 30.7963 6.4078 4.806 .0000 17.7595 43.8331

Slope 0.0343 0.0119 2.889 .0068 0.0101 0.0584