The results of one study determined that about 80% of the variation in students\

Question

The results of one study determined that about 80% of the variation in students' final exam scores is explained by the variation in the total number of hours spent studying during the semester. Suppose the final exam scores and hours spent studying during the semester are obtained for members of a class of 40 students. These data are used to run a regression. a. What is the independent variable? b. If you construct a scatter plot, which of the following most likely describes the trend you will observe? (Circle your choice.) i. From left to right, the plotted points will trend upwards. ii. From left to right, the plotted points will trend downwards. iii. There is no way to predict how the data will trend. c. Approximate r, the correlation coefficient, to three decimal places.

Explanation / Answer

Ans:

a)Indpendent variable is the total number of hours spent studying during the semester.

b)We are only given cofficient of determination, r2,which tells only strength of association,not direction of trend.

Hence,Option iii) is correct.

c) As,it is given that the 80% of the variation in student's final test scores is explained by the variation in the total number of hours spent studying during the semester.it means that cofficient of determination,r2 is 0.8

So,r=sqrt(0.8)=0.894

Cofficient of correlation,r=0.894

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