In: Statistics and Probability
number of absences | 6 | 2 | 15 | 9 | 12 | 5 | 8 |
final grade | 82 | 86 | 43 | 74 | 58 | 90 | 65 |
The data below were obtained in a study on the number of absences and the final grades (in percentages) of seven randomly selected students in a statistics class. Number of absences 6 2 15 9 12 5 8 Final grade 82 86 43 74 58 90 65 (2 4 6 8 10 12 14 5 0 6 0 7 0 8 0 9 0 absences g ra d e s) (this is just the scattered plot which i could not place here)
3 a) Consider the scatterplot of the data above and describe the association between the number of absences and the final grade. Is linear regression appropriate here?
b) Perform linear regression analysis in SPSS. Write down the linear regression equation that relates the final grades and the number of absences.
c) A 90% confidence interval for x = 10 is (58.996, 69.897). Interpret it.
d) Find a 95% confidence interval for the slope of the regression line.
e) Interpret the slope of the regression line.
f) Interpret the y-intercept of the regression line.
g) What assumptions do you need for performing the linear regression analysis in part b)?