Study: unmatched case-control study. Use the following suggestions to guide you when writing your original post: Describe this study design, discuss the strengths and weaknesses, and advantages and disadvantages of this study design. Using OpenEpi (http://www.openepi.com/Menu/OE_Menu.htm Links to an external site.) go to sample size, choose unmatched case-control; or using Epi Info ((http://wwwn.cdc.gov/epiinfo/ Links to an external site.) select statcalc, sample size, choose unmatched case-control and calculate the sample size needed for the following case-control study:

Researchers wanted to investigate if cases with polyps of the colon were more likely to be affected by diet compared to controls. The researchers set the confidence level at 95% and chose 80% power. How many cases and controls would be needed to detect an odds ratio of 1.5, if the ratio of control to cases is 2 and the anticipated percentage of control exposed is 25%?