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To: DannyTN

> But pre-covid odds are 40% according to the commercial.

No, this is not the odds. The odds is a value between 0 and infinity and therefore would never be expressed as a percentage. This value (40%) is the estimated proportion of the population over 50 with ED.

If the proportion is p then the odds is p/(1-p). So the probability p is a value between 0 and 1 (or 0% and 100%), while the odds is between 0 and infinity. In the example were discussing the odds is 0.4/(1-0.4) = 0.4/0.6=2/3.

Note that multiplying the odds by a factor (often called the odds ratio) is a sensible thing to do, while multiplying a probability (or proportion) by a factor can lead to nonsense (like the 120% value you obtained.)


55 posted on 04/04/2021 12:06:06 PM PDT by Qilin
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To: Qilin
Definition of odds
1a(1): the probability that one thing is so or will happen rather than another : CHANCES the odds are against it
(2): the ratio of the probability of one event to that of an alternative event

40% is the probability that a man over the age of 50 has ED, according to the commercial.

You're using the second definition, like gambling odds, 4 to 6 you have ED.

But still you can't use that ratio the way you are using it.

My undergraduate minor was in Math. I've had a lot of statistics and probability, including graduate level.

57 posted on 04/04/2021 12:36:06 PM PDT by DannyTN
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