STA 3024 Ch 12 solutions

# STA 3024 Ch 12 solutions - Solutions to even numbered...

This preview shows pages 1–2. Sign up to view the full content.

Solutions to even numbered problems in the suggested homeworks : Chapter 12 12.12a. Since the correlation coeﬃcient of height (with weight) is highest compared to that between (%BF, weight) and (age, weight), we conclude that height is the best predictor of weight. Here we can directly compare the correlations because r (correlation coeﬃcient) doesnot depend on units. b. This is because, if we add a new explanatory variable to a regression, the R 2 value either gets larger or at worst, stays the same (if the new explanatory variable is useless). c. No, age doesnot help us in predicting weight because on adding it, R 2 increases by only 1%(66% to 67%) (i.e the prediction error decreases by only 1%) which is negligible. 12.22a. The steps for the signiﬁcance test are as follows : 1. Assumptions : Please see my notes. Is the sample random or convenience ? 2. Hypotheses : H 0 : β 2 = 0 vs H a : β 2 6 = 0 3. Test Statistic : t = 1.39 4. P - value : 0.17 5. Conclusion: If the null hypotheses were true, the probability would have been 0.17 of getting a

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 2

STA 3024 Ch 12 solutions - Solutions to even numbered...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online