“Understanding Math to Live a More Informed Life” KEW Episode 98: The Normal Curve

Are you familiar with the ‘bell curve’? It’s also called a ‘normal curve’, or a Gaussian distribution because it describes what statisticians call a ‘normal distribution’. Here’s the wikipedia definition:

a probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean

And here’s a video link if you want a more detailed explanation.

Essentially, this picture is a visual image of how ‘typical’ things sort of fall out in the world.

Like size of largemouth bass. If you could remove every single bass from a lake, measure them all, and enter the number of each fish in each size class it would *theoretically* look like this.

If you could measure the height of every person on earth it drew vertical lines for the number of individuals in each size class (by total inches, for example) it would also *theoretically* look like this.

And the same goes for just about anything on earth you can measure. Theoretically.

I add the theoretical part because, for lots of reasons – mainly reality, things don’t always follow a normal distribution. Sexual selection, for example, may skew the human height graph one way or the other depending on mate preference for taller or shorter partners.

But so what, anyway? Well, the normal curve shows the probability of finding an example for a given characteristic. Like, how likely is it to find a man that is 4′ tall? This would fall in the very left hand tail of the bell curve representing a very low probability. Finding a 5’7″ person would be relatively easy, as it falls in the middle part of the ‘bell’.

So the cool thing about normal curves is that they visually illustrate some parameters. I like the say that statistics helps us understand how likely something is to happen. I talk about this in many Episodes including Fear and Analysis Paralysis. We often over or underestimate the likelihood of things happening to us, and normal curves are a way of illustrating reality.

For example, a lot of people have a fear of flying because they are afraid of a plane crash. If we could actually see the normal curve for flying success, or the probability of a crash or problem we might feel more at ease. Especially if we were to compare this figure to one that shows the probability of crashing in a car. Being able to visualize the relative sizes of probability, or chance, can help immensely.

Once you learn how to read a normal curve, you can understand quite a bit about the data. Normal curves show all kinds of statistics like the average, variance, range, maximum, and minimum values. These can also help you see the pattern, get a better idea of probability or likelihood, and feel better about your decision making.

As I say in the video below, averages are incredibly misleading estimates. We use them all the time to talk about things we might not really understand. Being able to more accurately interpret what is going on is a skill we can all develop to live better lives.

I have lots of exciting things coming up and share more in the full video and podcast. I will be starting a book and blogging about it starting with Episode 101. I am also releasing a new YouTube only project called ‘Being Better Being’ with my good friend Paul Gadola, you know him from multiple interviews on KEW.

So please follow, share, subscribe, and tell your friends so we can enjoy the future together.

Podcast audio download direct: https://pdcn.co/e/https://chtbl.com/track/CGDA9D/www.buzzsprout.com/530563/10639628-kew-episode-98-the-normal-curve.mp3?download=true

YouTube video link: https://youtu.be/9QvigYs6YLs