In this study, the probability of case exposed to oral contraceptive i 4.4 times higher that the probability of controls exposed to oral contraceptive.

We have 95% of confidence that in the population, the probability of cases exposed is between 2.5 and 7.7 times higher that the probability of controls exposed. If the lower limit was below 1, the data should be consistent with the probability of exposure was higher in controls than in cases.