Pretest/Correlation

At the beginning of the semester you were given a pretest. No one answered the questions correctly. Now, you should be able to do the questions below. We covered a lot this semester. After the pretest is additional work in correlation and regression.

418 -- Pretest -- don't panic -- show your work.

1. What is the correlation of X and Y?

X Y
_________

5 7
7 5
3 3

2. Ninety indie rock experts were asked which UK band of the early
1990s was the most influential:

20 responded that Primal Scream was.
30 responded that the Jesus and Mary Chain was.
40 responded that My Bloody Valentine was.

Do the experts like these three bands equally? Perform a chi-square
test (report the statistic).

3. Two types of behavioral therapy were attempted on six different patients.
The number of days required for recovery (for each patient) is shown:

Therapy A: 4, 5, 6
Therapy B: 9, 8, 10

Did it matter what kind of therapy a patient received? Do the appropriate t-test (report the
statistic).

END PRETEST

4. Correlation and Regression

variable X: 1, 7, 3, 4, 6
variable Y: 3, 9, 2, 6, 10

These numbers are paired (i.e., 4 and 6 would be a point in the scatterplot).

(a) Plot the scatterplot for these numbers (put X on the X axis, i.e., as the predictor).

(b) What is the correlation between these numbers?

(c) What is the regression line?

(d) Plot the regression line on the same plot as above.