8 Lessons From Statistics That Can Change Your Life

Most people hate statistics. I used to teach statistics for undergraduate students, and no one liked the class, no matter how hard I tried to make it interesting. (Maybe my examples from Saved by the Bell and Seinfeld were too outdated.) One thing I always tried to do was connect statistics to real life. So in that spirit, here are 8 lessons from statistics that can change your life:

1. Correlation does not equal causation. As humans, we tend to see two things occur together and infer meaning from it, thinking that one thing must have caused the other. But we know from statistics that correlation does not equal causation. Just because two things occur together, it doesn’t mean that one thing caused the other. In the same way, be cautious about inferring too much meaning when two things occur at the same time.
2. Regression to the mean. In statistics, if you notice an extreme data point (either very high or very low), the next data point is likely to be less extreme. In the same way, in life, if you have a very good or very bad day (or performance, game, or whatever), the next one is likely to be more average, statistically speaking. Thus, it’s usually a good idea not to get too high when things are good, or get too down when things are bad. Your next experience will probably not be quite as good (or bad).
3. The bell curve. Just about everything in life follows a general bell-shaped pattern. Most people are about average, with equal numbers of folks trailing off to either the high or low ends of the curve. Because of this, you are likely to be average at most things. If you are awesome at something (like basketball, chess, parenting, or whatever), it is probably because you have spent a large number of hours practicing that particular skill. Because we all have a limited amount of time, if you are awesome at one thing, you will probably be below average at most other things. That’s just the nature of life. Be okay with being average at most things. And if you do make the sacrifice to be awesome at something, recognize that you probably will be below average at most everything else.
4. The law of probability. In statistics, we are never certain about anything. When we make a conclusion, we say something like p < .05, which means there is less than a 5% chance that our findings are due just to chance. This is a low probability, but even so, our conclusion is tentative. Future research may disprove our conclusion, and that’s okay. In the same way, don’t be too certain about the conclusions you make in life. Be open to new data and experiences that may disprove what you believe to be true.
5. Focus on the effect size. In statistics, we often talk about something being “significant.” But all this means is that it is unlikely that we could have found our result completely due to chance. It doesn’t say anything about how large or meaningful the effect is. To answer that question, we need a different sort of statistic called an effect size. In the same way, pay attention to the effect size when something happens in your life. Often we get upset about something that happens, but the reality is that the impact this event has on our happiness is small. If the effect size is small, don’t let it ruin your day.
6. Consider your sample size. In statistics, we are more confident in a finding if we have a large sample size than if we have a small sample size. In the same way, in your life, pay attention to the number of data points. If you experience a similar problem in several settings or relationships, it might be something to take a look at. If you get feedback about a problem from several individuals in your life, take more stock in what was said than if it was just from one person.
7. Find the moderator variable. In research, if there are mixed findings, sometimes what is going on is that there is a moderator variable in play. A moderator variable is a variable that changes a relationship between two other variables. For example, the effect of stress on quality of life is different depending on one’s level of social support (moderator variable). If social support is low, stress has a big negative impact on quality of life. But if social support is high, there isn’t a difference in quality of life between people who have high vs. low levels of stress. In the same way, if something is confusing or inconsistent in your life, there might be a moderator variable lurking underneath the surface. If you are able to identify the moderator variable, you might increase your understanding of yourself, as well as your happiness.
8. Be careful of restricted range. In research, if one of your variables has a restricted range, meaning all the levels of the variable are pretty similar, it can be hard to find significant results. For example, the relationship between GRE score and success in graduate school is pretty low, but part of this problem is restricted range—most people who end up getting into graduate school have high GRE scores. In the same way, don’t make conclusions in your life based on a restricted set of opinions or experiences. Get a wide range of opinions or experiences, and THEN make your decision.

What lesson from statistics can you take with you today?