A vivid example can be very effective in reinforcing an idea in your speech, but for such a purpose you should be especially certain that it is a(n) example and not an exceptional case.

representative

Explanation:

When trying to reinforce an idea in a speech or an essay or any forms of writing, using a vivid example can be very effective in achieving this. However, these examples must be representative of the scenario or idea you are trying to avoid and not an exceptional case. Using an exceptional case can be regarded as a fluke, but once a representative case is used in your example, it goes a long way in buttressing the idea or point you are trying to make.

you probably know the answer. stop asking stupid questions and making me waste my time. j.k. ; )   b.t.w. what are three ratios equivalent to 5 : 11? thx