Statistics 227
Homework 6
Due Wednesday, 13 November 1996
- Selvin, Page 288, Problem 3. Omit the calculation of Pearson's
statistic, Yule's statistic (and the associated confidence interval), and the
phi-correlation.
- Selvin, Page 289, Problem 5.
- Selvin, Page 289, Problem 7. Calculation of measures of association is
not required.
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Black White
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N of High Low N of High Low
Characteristic Patients PSA PSA Patients PSA PSA OR (95% CI)
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Total 133 77 56 408 155 253 2.2 (1.5-3.3)
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Tumor grade:
Well 47 24 23 165 40 125 3.3
Moderate 74 42 32 215 98 117 1.6
Poor 12 11 1 28 17 11 7.1
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- The table above gives the breakdown of prostate specific antigen (PSA) in
Black and White men diagnosed with prostate carcinomas of different grades.
The questions of interest are:
- Are Black men more likely than White men to have an elevated PSA at
diagnosis?
- Is the likelihood of an elevated PSA affected by tumor grade?
(Well-differentiated tumors have a much better prognosis than do
poorly-differentiated tumors.)
Last updated 05-Nov-96
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