Hello there, I am a medical student and I would like to discuss a slightly confusing question that I got in a certain examination. Here it is:(adsbygoogle = window.adsbygoogle || []).push({});

A researcher wanted to study the association between breast cancer and oral contraceptive use. She selected 50 women diagnosed with breast cancer and 50 women not having breast cancer, and determined the use of oral contraceptives among those women. Forty women reported having used contraceptives, 25 of them were women diagnosed with breast cancer.

The researcher further wants to test if this association is statistically significant or not at alpha = 0.05

1. State the null and alternative hypothesis

2. Calculate the appropriate test statistic

3. What is your decision and conclusion based on the calculated value of test statistic if the critical value of test statistic is 3.841 at alpha = 0.05?

Other parts of this question merely revolved around calculating and interpreting odds ratio but this particular bit was confusing. We have no calculators or t/z score tables in the examination. And till now, I still haven't been able to decide on what test statistic exactly did it prompt because it doesn't seem right trying a guess at using t/z or chi square tests here.

I'm sorry if I'm overlooking the "obvious" here because I'm not very well versed in mathematics.

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# The appropriate test statistic?

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