27. In a ground water survey, the researcher collects x = pH of well water and y

Question

27. In a ground water survey, the researcher collects x = pH of well water and y = bicarbonate (parts per million) of well water. The researcher wants to use the least squares linear regression model because his professional knowledge shows that a higher level of pH of the well water indicates less bicarbonate. A sample of 34 ground water samples yields the following: x has a mean of 7.66 and a standard deviation of 0.50; y has a mean of 142.79 and a standard deviation of 55.79. The regression model can explain 11.53% of the variation in y. What is the slope of the researcher's regression line? a. 37.77 b. -37.77 c. 12.83 d. -12.83

Explanation / Answer

Ans:

cofficient of determination,r^2=0.1153

r=sqrt(0.1153)=0.3396

correlation is negative,so r=-0.340 (as higher level of ph indicates less bicarbonate)

slope,b=r*sy/sx=-0.3396*55.79/0.5=-37.77

Option b is correct.

Related Questions

Navigate

• Browse (All)
• Browse 2
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.