Question

In what follows use any of the following tests/procedures: Regression, confidence intervals, one-sided t-test, or two-sided t-test. The procedures should be done with 5% P-value or 95% confidence interval.

# of OpenLab visits     Final grade
2       40
8       85
10      80
9       84
15      90
7       72
5       50
4       59
8       85
10      70
7       66
7       70
5       63
4       60
4       59
11      79
3       82
9       90
10      82
9       76
14      85
6       73
5       41
4       56
8       80
10      70
7       66
9       88
5       65
4       70
4       62
11      90

1. What test/procedure did you perform? (5 points)

• a. One-sided t-test
• b. Two-sided t-test
• c. Regression
• d. Confidence Interval

2. Why did you choose this test/procedure? Because… (5 points)

• a. We are checking if number of visits influences final grade.
• b. We are checking if two averages are significantly different.
• c. We are checking if the average of one variable is larger than the average of the other variable.
• d. We are comparing the average final grade with a specific number.

3. What is the P-value/margin of error? (5 points)

• a. 7.19248E-07
• b. 3.59609E-07
• c. 2.55531E-06
• d. 4.161353

4. What is the Statistical interpretation? (5 points)

• a. The P-value is much smaller than 5% thus we are very certain that the slope is not zero.
• b. The P-value is much smaller than 5% thus the test result is conclusive.
• c. The P-value is much smaller than 5% thus we can claim that the number of visits to open lab sessions is related to final grade.
• d. The prediction interval for the true average final grade of students with 8 or more visits to open lab is [78.64454, 85.88879]

5. What is the conclusion? (5 points)

• a. We are confident that more visits to open lab sessions lead to higher final grades.
• b. We are confident that students with 8 or more visits to open lab sessions have average final grade greater than students with less than 8 visits.
• c. We are NOT confident that students with 8 or more visits to open lab sessions have average final grade greater than students with less than 8 visits.
• d. None of these.

Answer 1