# 892: Null Hypothesis

## 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 judgement 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 1%), we *reject* the null hypothesis, in this case saying that cell phones *do* increase cancer risk. Otherwise, we *accept* the null hypothesis, saying that cell phones *do not* increase cancer risk. This is how almost all scientific experiments, from high school biology classes to CERN, produce results.

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.

## Transcript

- [A student works at a desk.]

- 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)

- I would feel entirely justified punching someone who said that unironically. Pennpenn 108.162.249.205 00:59, 27 January 2015 (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)

Oh really. If you say it increased by 2% this year, then by 3% next year. It increased 3%. Unless you mean it will increase by 3% from LAST YEAR to NEXT YEAR. Then it really increased by 2% then .97%. But for this purpose let's throw that out and make it simple. It increased by 2% this year, and will increase by 3% next year. 50% isn't how much it increased, but how much the increase increased. That's called acceleration. The rate of increase per year is always 2 or 3%. So, 1% doesn't factor into this equation at all no matter how you do the math. The answer is 1.02*1.03. It increased by 5.06% over the last two years. 108.162.216.114 14:59, 18 August 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)

- They should be on 985: Percentage Points or 1102: Fastest-Growing --Pudder (talk) 11:35, 23 October 2014 (UTC)