A study looking at breast cancer in women compared cases with non- cases, and found that 75/100 cases did not use calcium supplements compared with 25/100 of the non-cases. Develop a table to display the data. Calculate the odds of exposure in cases and non-cases. Calculate the odds ratio using the cross-product ratio.

How did they get 79%?

In a survey of 1,150 women who gave birth in China in 2000, a total of 500 reported that they took multivitamin during the month before becoming pregnant. Calculate the prevalence (expressed in percentage) of in this group of multivitamin takers.

Calculate the risk ratio for each table below. Interpret the risk ratios and indicate which drug is associated with high mortality for the three tables. Calculate RRs to show the relationship between drug use and severity of asthma by creating a 2X2 table from the three tables below. Interpret the OR/RR estimate. Calculate RRs to show the relationship between severity of asthma and death by creating another 2X2 table from the tables below. Interpret the RR estimate. Determine whether there is confounding by severity of asthma in the relationship between drug use and asthma deaths. Use your responses in a, b and c above to answer this question. Draw a pictorial representation of cofounding using the three variables in this particular example. Is there effect modification by severity of asthma?