Remember, you must show your work for full credit on any
problems involving computation.MATH200 — Practice Quiz: Chapter 4 — 20 min
Work this like a regular quiz, using only your crib sheet. Give yourself a maximum of 20 minutes, then turn to the solutions and see how you did.
Remember, you must show your work for full credit on any
problems involving computation.
For a random sample of TC3 students, the number of hours of TV per day and the GPA were recorded. Results were as follows:
| TV hr/day, x | 1 | 8 | 3 | 2 | 6 | 1 | 3 | 7 | 4 | 9 |
|---|---|---|---|---|---|---|---|---|---|---|
| GPA, y | 3.2 | 2.7 | 3.1 | 3.7 | 2.9 | 3.0 | 2.9 | 2.5 | 3.0 | 2.6 |
(a) (points: 2) Make a scatter plot of these data on your calculator.
(b) (points: 3) Find the correlation coefficient and the equation of the line that fits these points best. Round to four decimal places, and label them with their proper symbols.
(c) (points: 2) Based on the regression, what is the expected GPA (accurate to two decimal places) for a student who watches 7 hours of TV daily? Use the proper symbol in your answer.
(d) (points: 2) Find the value of the residual for x = 7.
(e) (points: 2) The decision point for sample size 10 is 0.632. What if anything can you conclude about the relation between TV watching and GPA for all TC3 students?
2(points: 2)
A scatter plot is shown at right. Would the value of r be
strongly positive, near zero, or strongly negative?
Briefly explain your answer.
Solutions to this practice quiz are available at http://www.tc3.edu/instruct/sbrown/stat/