Determine whether the situation calls for service in observational study or experiment. You want to find out if years of lifting heavy weights has an affect on flexibility.

Step-by-step:

When I get a probability higher than  100% , what I do next depends on the circumstances:

If it is the result of a symbolic calculation, I double-check all my steps to see where I made a mistake.

If it is the result of an approximation by computer, and it is only a tiny bit larger, I might assume it is a rounding error.

If it is the result of an approximation by computer and the error is large, I double-check my calculations and my code.

If you are dealing with your basic probability theory, all your probabilities should be in the interval  [0,1] . There are some obscure versions of probability theory that allow for other values, but you’d only encounter those once you get to university level and specialize in this kind of thing.