We feel that the grade students get on the final exam are related to the amount of studying they do. To explore this, a sample of 17 students was gathered.
Grade Hrs Studied
99 8
97 5
94 7
94 6
93 8
92 4
91 7
86 5
85 4
82 6
81 7
80 3
75 2
73 3
73 4
72 2
71 3
Using Minitab, run correlation analysis and simple linear regression to study the relationship between Grade and Hrs Studied. Answer the questions below:
a. Analyze the Minitab output to determine the regression equation.
b. Find the coefficient of correlation. Interpret this value.
c. Does this data provide significant evidence (alpha=0.05) that the Hours Studied can be used to predict Grade a student gets on the final exam? Also interpret the p-value.
d. Predict the exam grade if a person studies 5 hours.
e. What is the 95% confidence interval for the mean exam Grade for students studying 7 hours?
f. What conclusions are possible using the meaning of and in this problem? (That is, explain the meaning of the coefficients.)
g. What conclusions are possible using the coefficient of determination (r-squared)?
h. What is the standard error? What does it mean?