Final answer:
An odds ratio of 4 indicates that an event is four times more likely to happen compared to an event with an odds ratio of less than 1. This means the event is far more likely than not occurring, with the group in question having 3 times the likelihood of experiencing the event when compared to a reference group with an odds ratio of 1.
Step-by-step explanation:
An odds ratio of 4 denotes that there is a four times more likely chance of XXX occurring. This means that the event in question is far more likely than not to happen when compared to another event with an odds ratio of less than 1.
If we are referring to the likelihood of an event when comparing two groups, such as a control group and an experimental group, then an odds ratio greater than 1 indicates increased odds of the event occurring in the experimental group. Specifically, in the context of health or medical studies, if the people in the exposed group have an odds ratio of 4, they are 3 times more likely to have the health event than those in the non-exposed group because the reference group's odds is considered to be 1.
In general betting terms, if the odds increase by a factor, it implies that the amount by which winnings would exceed the original bet is by that factor minus one. So, an odds ratio of 4 would give you a return that is 3 times your stake, which is why a ratio of 4 means 3 times more likely, and not four.