Stat 500 Homework 4 (Solutions)
Read in data and fit the model:
> library(faraway)
> data(teengamb)
> g = lm(gamble ~ sex + status + income + verbal, data = teengamb)
> summary(g)
Coefficients:
Estimate
(Intercept) 22.55565
sex
22.11833
status
0.05223
in
Ch2 summary
What is frequency table?
It is a grouping of qualitative data into mutually exclusive classes showing the number of
observation in each class.
Ex. Republican, democrat, or independent; or state of birth.
A relative frequency table shows the fr
Chapter 3 Summary
TR 12:15
Describing Data
A measurement of location is a value used to describe the center of a set of data.
A. the arithmetic mean is the most widely reported measure of location.
1. It is calculated by adding the values of that observat
Ch7 Summary
Continuous probability distributions
1. The uniform distribution is continuing his brother Billy Dee distribution with the
following characteristics:
A. It is rectangular in shape
B. The mean and the median are equal
C. It is completely descri
Chapter 4 summary
Describing Data
Displaying and Exploring Data
A dot plot shows the rang of values on the horizontal axis and the number of
observations for each value on the vertical axis.

Dot plot report the details of each observations.
They are use
Chapter 6 Summary
1. A random variable is a numerical value determined by the outcome of an experiment.
2. A probability distribution is a listing of all possible outcomes of fun experiment and the
probability associated with each outcome.
a. Add discrete
Chapter 5 summary
1 A proability is value between zero and one inclusive represent that likelihood a
particular event what happen
A. An experiment is the observation of some activity or the act of taking some
measurement.
B. And outcome is a particular r
Chapter 10: Model Selection
Stats 500, Fall 2016
Brian Thelen, University of Michigan
443 West Hall, [email protected]
1 / 27
Variable Selection
Testingbased approaches
Criterionbased approaches
2 / 27
Testingbased Model Selection
Backward elimination
STATS 500  Homework 5
Due Wednesday, November 9
Chapter 8, question 5 (page 131)
(a) Using the stackloss data, fit a model with stack.loss as the response and the other three variables as predictors using the following methods:
1. Least squares
2. Least
Chapter 6: Diagnostics
Stats 500, Fall 2016
Brian Thelen, University of Michigan
443 West Hall, [email protected]
1 / 52
Diagnostics
Checking error assumptions
Finding unusual points
Checking the structure of the model
2 / 52
Checking Error Assumptions
A
Chapter 7: Problems with Predictors
Stats 500, Fall 2016
Brian Thelen, University of Michigan
443 West Hall, [email protected]
1 / 28
Problems with Predictors
Errors in predictors
Change of scale
Collinearity
2 / 28
Errors in Predictors
Consider simple r
STATS 500  Homework 3
Solutions
Problem 2 in Chapter 3 of Faraway (page 49)
Add the following additional problems.
(f ) Derive 95% confidence intervals for the regression coefficients based on the linear model analysis
carried out in (a).
(g) Construct a
STATS 500  Homework 4
Due Wednesday, October 12, 2016
Based on Chapter 6, problem 2 (p. 97)
Using the teengamb dataset, fit a model to predict gambling expenditure from all other available variables.
(a) Perform regression diagnostics on this model to an
Chapter 9: Transformation
Stats 500, Fall 2016
Brian Thelen, University of Michigan
443 West Hall, [email protected]
1 / 24
Transformation
Transforming the response
Transforming the predictors
Why?
Nonlinearity
Heteroscedasticity
May improve fit
2 / 2
Stat 500 Homework 2 (Solutions)
The R output (only relevant part) for the fitted model is given below.
> library(faraway)
> data(teengamb)
> g<lm(gamble~.,data=teengamb)
> summary(g)
Coefficients:
Estimate Std. Error t value Pr(>t)
(Intercept) 22.55565
Chapter 8: Problems with Errors
Stats 500, Fall 2016
Brian Thelen, University of Michigan
443 West Hall, [email protected]
1 / 36
Problems with the Error
Recall N (0, 2 I)
Unequal variance
Correlated
Heavytailed
2 / 36
Weighted Least Squares
Errors u
Chapter 1 Summary
What Is Statistics?
Statistics, a small word means a lot and it is one of the most important terms to
study business and understand it. It is the science of collection, organizing, presenting,
analyzing, and interpreting data to assist i