Statistics 227

Homework 6
Due Wednesday, 13 November 1996


  1. Selvin, Page 288, Problem 3. Omit the calculation of Pearson's statistic, Yule's statistic (and the associated confidence interval), and the phi-correlation.
  2. Selvin, Page 289, Problem 5.
  3. Selvin, Page 289, Problem 7. Calculation of measures of association is not required.
  4. ============================================================================
                            Black                  White
                    ---------------------  ---------------------
                       N of    High  Low      N of    High  Low 
    Characteristic   Patients   PSA  PSA    Patients   PSA  PSA     OR (95% CI)    
    ----------------------------------------------------------------------------
    Total               133      77   56       408     155  253    2.2 (1.5-3.3)
    ----------------------------------------------------------------------------
    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
    ============================================================================
    

  5. 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:
    1. Are Black men more likely than White men to have an elevated PSA at diagnosis?
    2. 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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