Question

In: Statistics and Probability

4. A statistical researcher wishes to investigate the relationship between a student’s study time and their...

4. A statistical researcher wishes to investigate the relationship between a student’s study time and their ultimate exam grade for that exam. The following data is determined:

X=study time(hours)

4

7

8

9

12

Y=exam grade (1 to 25 scale)

11

16

14

22

17

Ex=40     Ex2=354          and Exy=670

Ey=80      Ey2=1346

  1. Sketch the scatter diagram. Does the trend appear to be positive or negative?
  2. given that E(x-xbar)2=34, Please use that comment to help determine the sample standard deviation for the X data.
  3. Given that [n*Ey2-(Ey)2]=330, Please use that comment to help determine the sample standard deviation for the Y data. explain
  4. Please determine the regression equation “y=a+bx” for these data. explain
  5. Please use your Part D regression equation to predict the exam grade for the sixth student who happened to take 10 hours to study for the exam. explain
  6. please determine the sample linear correlation coefficient for this data. explain

Solutions

Expert Solution

4.(a)

The trend appear to be positive.


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