The following data are from a random sample of 10 students who participated in a study undertaken to investigate the effect of sleep time (measured in average number of hours of sleep per night) on GPA (grade point average, measured on a 4-point scale).
Student |
Sleep time |
GPA |
1 |
7 |
3.28 |
2 |
9 |
3.16 |
3 |
8 |
3.75 |
4 |
6 |
2.50 |
5 |
4 |
2.45 |
6 |
8 |
2.91 |
7 |
7 |
3.53 |
8 |
6 |
3.02 |
9 |
3 |
2.30 |
10 |
8 |
3.48 |
a. Find the equation between GPA (y) as function of sleep time (x).
b. What is the estimated GPA of a student who averages 5 hours of sleep per night?
c. What is the coefficient of determination?
using excel>data>data analysis>Regression
we have
SUMMARY OUTPUT | ||||||
Regression Statistics | ||||||
Multiple R | 0.77235 | |||||
R Square | 0.596524 | |||||
Adjusted R Square | 0.546089 | |||||
Standard Error | 0.334186 | |||||
Observations | 10 | |||||
ANOVA | ||||||
df | SS | MS | F | Significance F | ||
Regression | 1 | 1.320919 | 1.320919 | 11.82769 | 0.008835 | |
Residual | 8 | 0.893441 | 0.11168 | |||
Total | 9 | 2.21436 | ||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | |
Intercept | 1.70537 | 0.401641 | 4.246003 | 0.002814 | 0.779184 | 2.631557 |
sleep time | 0.201914 | 0.05871 | 3.439141 | 0.008835 | 0.066527 | 0.3373 |
a. the equation between GPA (y) as function of sleep time (x) is
y =1.70537+0.201914 *x
b. the estimated GPA of a student who averages 5 hours of sleep per night is
y =1.70537+0.201914 *5 = 2.715
c. the coefficient of determination is 0.5965
Get Answers For Free
Most questions answered within 1 hours.