Statistics Homework Solutions 168

Statistics Homework Solutions 168 - 168 CHAPTER 7 Chapter 7...

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Unformatted text preview: 168 CHAPTER 7 Chapter 7 Section 7.1 ¥ ¥ y 2 y 2 28, ∑n i 1 xi x yi y 23. 0 8214. ¡ ¡ ¥ ¡ ¤ ¦¥ ¡ yi yi ¨ ¡ ¤ ¡ ¤ ¥ ¡ ¤ ¡ x y ∑n 1 i ¤ x yi 2 1 ¡ ¡ xi 28, ∑n i ¥ xi 2 ¡ ¡ ∑n 1 i x r ∑n 1 i xi ¤ 1 ¡ 4, ∑n i ¤ ¦¥ y ¡ x ¡¥ ¤ 1. 3. (a) The correlation coefficient is appropriate. The points are approximately clustered around a line. (b) The correlation coefficient is not appropriate. The relationship is curved, not linear. (c) The correlation coefficient is not appropriate. The plot contains outliers. 5. The heights and weights for the men (dots) are on the whole greater than those for the women (xs). Therefore the scatterplot for the men is shifted up and to the right. The overall plot exhibits a higher correlation than either plot separately. The correlation between heights and weights for men and women taken together will be more than 0.6. 7. (a) Let x represent temperature, y represent stirring rate, and z represent yield. ¡¥ z 424 15. ¡ ¤ ¦¥ ¡ ¡ ¤ ¡ ¥ ¤ ¡ ¡ ¨ ¡ ¡ ¨ ¡¥ ¥ ¤¥ ¡ ¡ ¡ ¤ ¤ The correlation coefficient between temperature and yield is ∑ n 1 xi x z i z i r 0 7323. ∑ n 1 x i x 2 ∑ n 1 zi z 2 i i ¨ ¡ ¥ ¥ ¡ ¤ ¦¥ ¤ ¡ ¤ ¡ ¥ ¡ ¤ ¡ The correlation coefficient between stirring rate and yield is ¨ ¨ y zi ¤ yi ¤¥ ¨ 1 ¡¥ ¤ ¡ 2 ¥ xi 1360, ∑n 1 zi i x zi z 481 63125, ∑n i y ¡ ∑n 1 i 75 590625, ∑n 1 xi x 2 1845 75, i z 2 234 349694, ∑n 1 xi x yi y i ¡ yi 1 45, z ¨ ∑n i 119 875, y ¡ Then x 1436, ...
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