Imagine that you are a college professor. You notice that fewer students appear to attend class on Friday afternoons when the weather is warm than when it is cold outside. To test your hunch, you collect data regarding outside temperature and attendance for several randomly selected weeks during the academic year. Your data are as follows:
| Temperature (degrees F) |
Attendance (number of students) |
| 58 |
85 |
| 62 |
83 |
| 78 |
64 |
| 77 |
62 |
| 67 |
66 |
| 50 |
86 |
| 80 |
60 |
| 85 |
82 |
| 70 |
65 |
| 75 |
62 |
a. Draw a scatter plot of the data.
b. Do the data appear to be roughly linear?
c. Do you see any evidence of outliners?
d. From examining the scatter plot, does there appear to be a correlation between temperature and attendance? H so, is it positive or negative?
e. Calculate r for these data.
f. Is this correlation statistically significant?
g. Interpret r. What does r tell you about the relationship between temperature and attendance?