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Conceptual questions
Relationships between
quantitative variables
1. How do we determine:
a. the direction of a
relationship?
b. the strength of a relationship?
c. whether a relationship is significant?
2. How can we predict the
value of one variable based on another
variable?
Estimation
3.
Suppose that you want to see how effective
practice is for math skills. After a practice
test you find that 250 students get an average
score of 212, with a sample standard deviation
of 40. What the point estimate of the
population mean?
Chi-Square
4. What type of variables require this type of
test?
Computational questions
For the following
problems, use the decision tree and
tables provided below. Assume α = 0.05,
unless otherwise noted.
Tables
5. A professor
of philosophy hypothesizes that an intro
course in logic will help college students
with their studies. To test this hypothesis,
he selects a random sample of n =
25 freshmen. These students are required to
complete a logic class during their first
year. At graduation, the GPA for each
student is recorded. The mean GPA for the
sample is 2.83. Knowing that Sums of Squares
= 6, find point estimate and 95% confidence
interval for the mean GPA for students who
take the logic course.
6. Suppose that you are
interested in whether there is a gender
effect for sport preference among sports
fans. So you ask several sports fans at a
sports bar which they like better, football
or basketball. The raw data are presented
below. Use SPSS to answer your question.
| Person
number |
Sex |
Football fan |
| 1 |
Male |
Basketball
fan |
| 2 |
Female
|
Football
fan |
| 3 |
Male |
Basketball
fan |
| 4 |
Male |
Football
fan |
| 5 |
Female
|
Basketball
fan |
| 6 |
Female
|
Basketball
fan |
| 7 |
Male |
Football
fan |
| 8 |
Male |
Basketball
fan |
| 9 |
Male |
Basketball
fan |
| 10 |
Female
|
Football
fan |
| 11 |
Female
|
Basketball
fan |
| 12 |
Female
|
Basketball
fan |
| 13 |
Female
|
Football
fan |
| 14 |
Female
|
Football
fan |
| 15 |
Female
|
Football
fan |
|
| 16 |
Female
|
Basketball
fan |
| 17 |
Male |
Basketball
fan |
| 18 |
Male |
Football
fan |
| 19 |
Female
|
Basketball
fan |
| 20 |
Male |
Basketball
fan |
| 21 |
Female
|
Basketball
fan |
| 22 |
Male |
Basketball
fan |
| 23 |
Male |
Basketball
fan |
| 24 |
Male |
Football
fan |
| 25 |
Male |
Football
fan |
| 26 |
Female
|
Football
fan |
| 27 |
Female
|
Basketball
fan |
| 28 |
Male |
Basketball
fan |
| 29 |
Female
|
Basketball
fan |
| 30 |
Female
|
Basketball
fan |
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7. Many people report that
they don't like spicy food because they
experience stomach discomfort after eating it.
Chef Tukey believes that his new SuperSpice
can not only make any food taste great but
also reduce stomach discomfort. His marketing
firm asks a sample of individuals to eat spicy
food for 1 week and report how often they
experience stomach discomfort. Then they are
given some SuperSpice and told to use it on
all of their spicy food for another week. They
also report the number stomach problems that
week. The data are on the number of stomach
problems was as follows:
| Person |
Before
SuperSpice |
After
SuperSpice |
| A |
4 |
0 |
| B |
0 |
0 |
| C |
5 |
3 |
| D |
4 |
3 |
| E |
9 |
2 |
| F |
8 |
0 |
| G |
6 |
6 |
Use SPSS to test the
hypothesis that SuperSpice reduces stomach
discomfort and find the 95% confidence
interval for the the effect of SuperSpice on
the likelihood of stomach problems.
8. Suppose you conducted a
Pearson r test and found the
relationship between two variables to be r
= -.54 with df = 25. Assume α= .05
and a 2-tailed test. Find the critical
r-values.
Since this is a review lab,
I've provided the solutions here.
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