Question

Help. Stuck on these last two! Will give a THUMBS UP for correct answers! :)

85. V MY NOTES A study of class attendance and grades among first-year students at a state university showed that in general students who attended a higher percent of their classes earned higher grades. Class attendance explained 2 = 36% of the variation in grade index among the students. What is the numerical value of the correlation between percent of classes attended and grade index? (Use 2 decimal places.) 86. MY NOTES An owner of a home in the Midwest installed solar panels to reduce heating costs. After installing the solar panels, he measured the amount of natural gas used y (in cubic feet) to heat the home and outside temperature x (in degree-days, where a day's degree-days are the number of degrees its average temperature falls below 65° F) over a year-long period. He then computed the least-squares regression line for predicting y from x and found it to be y = 84 + 13x. Assuming a strong correlation, what is the predicted amount of gas used when the outside temperature is 16 degree-days? cubic ft

Answer 1

Page No.: Youvi Date: 6 Given: r2 = 36% = 36/100 - r= vr2 = 0.36 = . Ans: 10.6 = 0.36 10.6 Given: Y = = Natural gas Temperature (in cubic feet) (in degree-days) x Regression line ů = 84 + 13 * x Given & Value of temperature (x)=16 in given regression so, plug the value of equation, and calculate x = 16 Ý Hence, we get * 16 y = 84 + 13 = 84 + 208 = 292 Ans: 292 ) cubic ft v