The following data gives the number of hours 10 students spent studying and their corresponding grades on their midterm exams. Hours Spent Studying 0.5 1 2 2.5 3.5 4 4.5 5 5.5 6 Midterm Grades 60 63 69 72 78 81 84 87 90 96 Step 3 of 3 : Calculate the correlation coefficient, r. Round your answer to three decimal places.

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Answer:

[tex]r=\frac{10(2892)-(34.5)(780)}{\sqrt{[10(151.25) -(34.5)^2][10(62100) -(780)^2]}}=0.9975[/tex]  

The final answer would be the correlation coefficient r =0.9975

Step-by-step explanation:

For this case we have the following data given:

x: 0.5 1 2 2.5 3.5 4 4.5 5 5.5 6

y: 60 63 69 72 78 81 84 87 90 96

And we want to calculate the correlation coefficient, and we have the following formula to do this:

[tex]r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2 -(\sum x)^2][n\sum y^2 -(\sum y)^2]}}[/tex]  

For our case we have this:

n=10 [tex] \sum x = 34.5, \sum y = 780, \sum xy = 2892, \sum x^2 =151.25, \sum y^2 =62100[/tex]  

And replacing we got:

[tex]r=\frac{10(2892)-(34.5)(780)}{\sqrt{[10(151.25) -(34.5)^2][10(62100) -(780)^2]}}=0.9975[/tex]  

The final answer would be the correlation coefficient r =0.9975