Sociology 63993
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Exam 1
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Page 1
Sociology 63993
Exam 1
February 18, 2011
I.
True-False.
(20 points) Indicate whether the following statements are true or false.
If false,
briefly explain why.
1.
A data set contains a few extreme outliers. It is usually best to use Stata’s
rreg
(Robust
Regression) routine to deal with the problem.
2.
The independent variables in an analysis include X1, X2, and X1X2 (i.e. X1 * X2). X1
has missing data (and hence X1X2 does too). If multiple imputation is being used, you should
first compute X1X2, and then impute the missing values for X1 and X1X2.
3.
Cronbach’s Alpha is used to test for serial correlation.
4.
The less true variability there is in a population, the higher the reliability of measures will
tend to be.
5.
The most extreme outliers on Y (i.e. the cases where Y is furthest from the mean) will
always have the most influence on the regression line.
II.
Short answer.
Discuss all three of the following problems. (15 points each, 45 points
total.)
In each case, the researcher has used Stata to test for a possible problem, concluded that
there is a problem, and then adopted a strategy to address that problem. Explain (a) what problem
the researcher was testing for, and why she concluded that there was a problem, (b) the rationale
behind the solution she chose, i.e. how does it try to address the problem, and (c) one alternative
solution she could have tried, and why. (NOTE: a few sentences on each point will probably
suffice
–
you don’t have to repeat everything that was in the lecture notes.)
II-1.
. sum income white male age fathered
Variable |
Obs
Mean
Std. Dev.
Min
Max
-------------+--------------------------------------------------------
income |
812
16.96983
8.464258
.5
25
white |
812
.864532
.3424337
0
1
male |
812
.4864532
.5001245
0
1
age |
812
38.53695
11.92651
18
81
fathered |
695
11.44173
3.838113
0
20

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