The following output summarizes the fit of an analysis of covariance to the data in Exercise 35. The variable D denotes a dummy variable, with D = + for values colored green and 0 otherwise.
(a) Does the fit of the model suggest parallel equations for the two groups?

(b) How would the output change if the coding of the dummy variable D were reversed (so that 0s became 1s and vice versa)?
(c) What should be the next step in analyzing these data, specifically thinking of the form of the fitted model?

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Estimate Std Error t-Statistic p-Value 0.2090 28.94 0.0001 2.0340 0.1800 11.30 <0.0001 11.85 <0.0001 0 28 Intercept 6.0486 5.9992 0.5063 -11 D×X -0.1865 0.2645-0.71 0.4843