# Extra credit stats

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Stat 30100 Bonus Real World for Extra credit Brady Spence This problem set uses the same dataset as before, MSLGrades.xls, with the student weight information. We will use Statcrunch to perform all statistical analyses on the dataset. Open the MSLGrades.xls dataset in Statcrunch. Copy and paste all output into the document. Make sure to answer all questions fully. We want to model the Final Grade percentage by the amount of time spent by the students on study plan weekly. At first Create the variable WeeklySPTime just like you did for RW2. 1.) Draw a scatterplot of WeeklySPTime and FinalGrade and paste the statcrunch output. 2.) What is the explanatory variable? WeeklySPtime 3.) What is the response variable? FinalGrade 4.) Describe the form, direction, and strength of the scatterplot. This scatterplot shows all the dots occurring in the positive half, they're spread out, but you can see some grouping in the upper left of this graph. Because these dots are spread out, we can conclude that this has a weaker relationship. Also, a value of R near 0 whether positive or
Stat 30100 Bonus Real World for Extra credit negative implies no correlation or a weak correlation as we can see above. There is an upward/positive trend to the direction. 5.) Lookup how to fit a linear regression equation of FinalGrade by WeeklySPTime in Statcrunch. Paste the output. 6.) What is the correlation? a. Give the value. 0.15783896 b. Looking at the Table in the book (A-5), what is the critical value for the correlation to be significant with α=0.05. Is the correlation significant? Should we conduct regression? The critical value would be 0.254 . Because the absolute value of r is less than the critical value we can conclude there is not sufficient evidence to support the claim that there is linear correlation. Becuase it is not sufficient we should not use the equation, instead y is equal to the mean of y values 7.) What is the expected FinalGrade of a student who spends 120 minutes on Mylab per week? Because the equation is not significant, we find the mean of the y-values (FinalGrade) to get the given value and you get 85.15% for the student