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2/14/2011
1
Lecture 7: February 14, 2011
Readings
•
Two
‐
Sample Hypothesis Tests: Chapter 10, pages 390
‐
401
–
Two scenarios relating to the test statistic:
•
Assume unequal variances (We did this last Wednesday).
•
Assume equal variances (We’ll do this today).
•
Next class:
–
Two
‐
Sample Hypothesis Tests: Paired Samples, pages 404
‐
409
•
Homework 5
opened at 10:00 p.m. February 11:
–
Page 401: Problem 10.2–Two
‐
sample test, assume unequal variances
–
Homework 5 closes Tuesday, February 15, at 6:00 p.m.
–
Unlimited tries until it closes! Feedback!
•
Homework 6
opens at 11:00 p.m. February 14:
–
Page 401: Problems 10.4 and 10.6–Two
‐
sample test, assume equal variances
–
Homework 6 closes Thursday, February 17, at 6:00 p.m.
–
Unlimited tries until it closes! Feedback!
•
Non
‐
Connect
Practice
problems:
–
Page 401: Problem 10.7–Two
‐
sample test, assume unequal variances
–
Page 401: Problem 10. 5–Two
‐
sample test, assume equal variances
–
Answers are in the back of the book.
–
If you need help with these, see a TA during office hours.
Go to
Worked
‐
Out Problems
on My Web Site
•
New
Worked
‐
Out Problems (
available Tuesday afternoon)
–
Page 401: Problems 10.3–Two
‐
sample test, assume
unequal variances
–
Page 401: Problems 10.4–Two
‐
sample test, assume
equal variances
•
Steps
•
Visual
•
p
‐
value
•
If you do not understand any part, ask in discussion. This
will be the first item of business during discussion.
Two Ways To Proceed
•
Last class we
assumed
that the true
variances
for the two groups are
unequal
.
•
This class we
assume
that the true
variances
for the two groups are
equal
.
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2
Hypothesis Tests For Comparing Two Population Means
Treat
σ
as not known and estimated by s
(Text pp 392
‐
401)
Do fraternity people perform at a level that is academically lower
than non
‐
fraternity people?
A university administrator wants to test the null hypothesis that the
mean GPA of fraternity members (F) and non
‐
fraternity members
(N) is the same versus the alternative that the mean for F is less
than the mean for N. (If the alternative upholds, serious corrective
action is to be taken). To test the hypothesis (at the 0.05 level) she
generates the following sample data:
X
F
=2.03
s
F
=0.6
n
F
=40
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This note was uploaded on 10/13/2011 for the course FINOPMGT 250 taught by Professor Kouzehkanani during the Spring '08 term at UMass (Amherst).
 Spring '08
 KOUZEHKANANI

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