Correlation coefficent (r) and explained variance (r²)

All learned from Claude Sonnet 3.5

[Variance is not as important for the beginners bc it’s squared SD different than explained variance] Variance

What is p value?

You run an experiment and ask: how often would random noise produce something like this? p = 0.05 → 5%, p = 0.9 → 90%

Due to the replication crisis, researchers want to redefine the standard threshold from P < 0.05 to P < 0.005..005."

Probability of distribution shapes

• normal (gaussian) – bell curve eg. IQ

• uniform – eg. rolling a side of a dice

• All types

Standard deviation (SD) (or rather Mean absolute deviation (MAD)) (in research used as d.)

Standard deviation (SD) is an averaged distances to the mean. Not quite bc this exactly is called mean absolute deviation (MAD) but this gives you the concept.

Low standard deviation – male hair (all rather short)

High standard deviation – women hair (all different lengths)

• Difference between Standard deviation (SD) and Mean absolute deviation (MAD)
• Male hair example - calculating SD

https://www.youtube.com/watch?v=gpKEfVZlPj4