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 two-tailed 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 confidence limits for the slope. (e) Verify that F = for the slope. (f) In your own words, describe the fit of this regression.

(a) y = 30.7963 + 0.0343x

(b) degrees of freedom = 33; t critical = 2.035

(c) 0.0101 and 0.0584 – slope is greater than zero

(d) Interval indicates slope is not significantly different than zero

(e) F = t^2 = 8.35 = 2.890