I’m starting to get into science a lot more these days but I do not know what p values and null hypothesis are.
Appreciate the help. Thank you.
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When we’re doing science, we’re trying to prove that our new idea is _wrong_, not right.
The Null Hypothesis is what we knew before we had our new idea, i.e. what we’ll see if our new idea _is_ wrong.
The _p_ value is the probability that results are due to luck rather than our idea being correct. When we design an experiment, we usually aim for a p of less than 5% (0.05).
Example. A coin is equally likely to flip heads or tails (this is the null hypothesis) but I think my coin always flips tails (my hypothesis). If I plan to flip once, and it’s a tail, I’ve disproven the null hypothesis and proven my hypothesis — but there was a 50% chance it was a fair coin that just happened to flip tails, so no-one would care about my result. So, instead, I plan to flip the coin six times. That way, if I flip all tails, there’s only a 4% chance that it was luck (p of 0.04).
Note that we might flip five tails and a head. In that case, we’ve failed to prove the coin always flips tails (yay, science!) , so we failed to prove our hypothesis, so the null hypothesis remains. So we make a new hypothesis, design a new experiment, and …
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