Stat 665 (Spring 2011)
Kaizar
Solutions 5
Exercises 20 points total
1. Problem 3.11, b and c
(b) Using R, I found the following output:
(Intercept)
x
Estimate Std. Error z value Pr(>|z|)
1.6094
0.1414 11.380 < 2e-16 *
0.5878
0.1764
3.332 0.000861 *
The pr
Stat 665 (Spring 2011)
Kaizar
Homework 2
Due at the beginning of class, Friday April 15.
Aim of Homework: To think about dierent kinds of categorical data. To apply dierent measures
of association in two-way tables. To perform tests of independence.
Readi
Stat 665 (Spring 2011)
Kaizar
Solutions 6
Exercises 40 points total
1. (8 points) Problem 4.8
(a) From the R output:
Coefficients:
Estimate Std. Error z value Pr(>|z|)
(Intercept) -3.6947
0.8802 -4.198 2.70e-05 *
wtkg
1.8151
0.3767
4.819 1.45e-06 *
The pr
Stat 665 (Spring 2011)
Kaizar
Homework 5
Due at the beginning of class, Friday May 6.
Aim of Homework: To practice computing with GLMs.
Reading: An Introduction to Categorical Data Analysis, 2nd edition: Chapter 3.
Exercises: 20 points total
1. (5 points)
Stat 665 (Spring 2011)
Kaizar
Homework 4
Due at the beginning of class, Monday May 2.
Aim of Homework: To practice working with GLMs.
Reading: An Introduction to Categorical Data Analysis, 2nd edition: Chapter 3.
Exercises: 40 points total
1. (8 points) A
Stat 665 (Spring 2011)
Kaizar
Homework 6
Due at the beginning of class, Friday May 20.
Aim of Homework: To apply, evaluate and interpret logistic regression models for categorical
responses and either categorical or continuous expanatory variables.
Readin
Stat 665 (Spring 2011)
Kaizar
Homework 7
Due at the beginning of class, Friday May 27.
Aim of Homework: To interpret models to t multivariate outcomes. To t and interpret loglinear models.
Reading: An Introduction to Categorical Data Analysis, 2nd edition
Stat 665 (Spring 2011)
Kaizar
Solutions 4
Exercises 40 points total
1. Toothpaste experiment:
(a) The outcome of interest is cavity 2, the number of cavities after 2 years of treatment.
(b) Any of the variables gender, age, uoride, and oss might be modera
Stat 665 (Spring 2011)
Kaizar
Solutions 2
Exercises 40 points total
1. (8 points) Agresti 2.16
(a) Response: lung cancer
Explanatory: have smoked (or not)
(b) case-control study
(c) No. This would be looking at the probability of cancer conditional on the
Stat 665 (Spring 2011)
Kaizar
Solutions 1
Exercises 40 points total
1. (6 points) Agresti problem 1.8 (use both the score and exact methods dont use Wald!)
(a) pi =
y
n
=
344
1170
= 0.294.
(b) The wording of the question is unclear as to the null hypothes
Stat 665, Spring 2011, Kaizar
Log-Linear Piano Example
Pianos
Orchestra
Boston
Chicago
Cleveland
Minnesota
New York
Steinway
36
156
121
22
99
Piano Type
Other
18
12
20
22
22
Pianos
Boston
140
120
100
80
60
40
20
Chicago
Cleveland
Minnesota
NewYork
Steinwa
Stat 665 (Spring 2011)
Kaizar
Homework 3
Due at the beginning of class, Monday April 25.
Aim of Homework: To think about dierent kinds of categorical data. To apply dierent measures
of association in two-way tables. To perform tests of independence.
Readi
Stat 665 (Spring 2011)
Kaizar
Homework 1
Due by the beginning of class, Friday April 8.
Aim of Homework: To review concepts of Wald, score and likelihood ratio testing. To review
concepts of tests and condence intervals for binomial proportions. To unders
Stat 665 (Spring 2011)
Kaizar
Conditional Association
1
Estimating Conditional Association under Homogeneity: Fixed
Eects
1.1
Mantel-Haenszel Statistic
K
k =1
Var log M H
=
1
2R 2
n11k n22k
n+k
K
k =1
M H =
n12k n21k
n+k
1
k
n+k
=
K
k =1 Rk
K
k =1 Sk
=
R
Stat 665 (Spring 2011)
Kaizar
Airline Example
Delay
on time delay Total
American
5317 3237 8554
Airline
United
1170
793 1963
Total
6487 4030 10517
=
5317793
11703237
= 1.113
Pearsons Chi-Squared: X 2 = 4.4112, df = 1, p-value = 0.03570
Likelihood Ratio: G
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http:/junkcharts.typepad.com/
7/26/11
STAT 665: Examples
77
From: Alan Agre
3/28/2011
STAT 665: Examples
1
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3
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http:/junkcharts.typepad.com/
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STAT 665: Examples
7
From: Al