HS312: Epidemiology and Biostatistics II - 1505A

Print by: Brittnee Roberts HS312: Epidemiology and Eiostatlstics II - 15O5A / HS3t2 Unit 1O Assignment

' Unit 6, Topic 25, Exercise 25-22 Preventing Breast Gancer

The Study of Tamoxifen and Raloxifene (STAR) enrolled more than 19,000 postmenopausalwomen who

were at increased risk for breast cancer. Women were randomly assigned to receive one of the drugs (tamoxifen or raloxifene) daily for five years. DurinE the course of the study, researchers kept track of which women developed invasive breast cancer and which women did not. The initial results released in

April 2006 revealed that 163 of 9?26 women in the tamoxifen group had developed invasive breast

cancer,compared to 16? of the 9745 women in the raloxifene group.

a, organize this information into " 2 * 2 t"ut..

Tamoxifen Raloxifene Totat

Breast Cancer

No Breast Cancer m Iotal

*7 n *8 b. Calculate the expected counts, under the null hypothesis that the population proportions of women who would develop breast cancer are the same with both treatments.

Round your answers to three decimal places.

Tamoxifen Raloxifene

Breast Cancer l*to 1",

No Breast Cancer t l*t, l*'= c. Conduct a chi-square test on these data. Report the hypotheses, test statistic, and P -value. Summarize your conclusion.

Round the test statistic to three decimal places. Use the chi-square distribution table to find a range for

the P -value. If there is no lower limit on the P -value, enter 0 for the lower limit. If there is no upper

limit on the P -value, enter 1 for the upper limit.

lfCIlrfuroxifrn

ffai4rarnoxifen

4F.alorifene

4Raloxifane

The test statistic i, X2 =

4 F -value 4

ffs.

d. Suppose sorneone else decided to perform a two-sample e -test and found that u = - 0'2 and F

-value = 0'838 Comment on how this compares to the test statistic and P -value you just calculated.

The test statistic of the chi-square test ls roughly

sample ' -test.

Answer *L: exact number, no tolerance Ancwer *22 exact number, no tolerance Angwer *3: exacf number, no tolerance Answer *4= exact number, no tolerance Answer *5: exact number, no tolerance Answer *62 exact number, no tolerance Angwer *?t exact number, no tolerance Answer *8: exacf number, no tolerance Answer *9: exacf number, no tolerance Ansrrer *1O: fhe absolute tolerance is +/-0.001 Answer *11: the absolute tolerance is +/-0.001 Angwer *LZ,z the absolute tolerance is +/-0.001 Answer *13: fhe absolute tolerance is +/-0.001 Answer *14: the absolute tolerance is +/-0.A01 Ancwer *15: exacf number, no tolerance Answer *161 exact number, no tolerance

the test statistic of the two-

Queetion Attempts: O of 5 used

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