# 892: Null Hypothesis

## [edit] Explanation

This comic is based on a misunderstanding. The null hypothesis is the hypothesis in a statistical analysis that indicates, essentially, the "status quo." For example, the null hypothesis for a study about cell phones and cancer risk might be "Cell phones have no effect on cancer risk." The *alternative hypothesis,* by contrast, is the one we want to prove or disprove - in this case, probably "Cell phones increase cancer risk."

After conducting a study, we can then make a judgment based on our data. There are statistical models for measuring the probability that a certain result occurred by random chance, even though in reality there is no correlation. If this probability is low enough (usually meaning it's below a certain threshold we set when we design the experiment, such as 5% or 1%), we *reject* the null hypothesis, in this case saying that cell phones *do* increase cancer risk. Otherwise, we *fail to reject* the null hypothesis, as we have insufficient evidence to conclusively state that cell phones increase cancer risk. This is how almost all scientific experiments, from high school biology classes to CERN, draw their conclusions.

It is very important to note that a null hypothesis is a specific statement relative to the current study. In mathematics, we often see terms such as "the Riemann hypothesis" or "the continuum hypothesis" that refer to universal statements, but a null hypothesis depends on context. There is no "*the* null hypothesis." It refers to a method of statistical analysis, not a *specific* hypothesis. Given that, Megan's response would probably be to facepalm.

## [edit] Transcript

- [A student works at a desk, and Cueball is talking to Megan.]
- Cueball: I can't believe schools are still teaching kids about the null hypothesis.
- Cueball: I remember reading a big study that conclusively disproved it
*years*ago.

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# Discussion

If you get a 50% discount at two shops and buy stuff from both of them, you have a 100% discount. Math. That's how it works, bitches. __Davidy__²²`[talk]` 10:05, 9 March 2013 (UTC)

That's a misleading thing about percentages. Like this: Prices of coffee increase by 2% this year, then by 3% next year. That's a 1% increase between years, or a 50% increase between years (from 2 to 3). So which is it? 1 or 50? 141.101.98.240 08:26, 18 December 2013 (UTC)

That's why they've invented the "base points" in financials, to denote the percentages of percentages. It's 1% absolute but 50bpp (base point percentage). 108.162.246.11 18:35, 20 January 2014 (UTC)

Don't these discussion points belong in a different comic? Or perhaps the garbage? Except (1), he lol'd me. 108.162.219.58 21:23, 5 February 2014 (UTC)