Stats: What is a “Standard Normal Distribution”?

https://www.youtube.com/watch?v=c11d3vVM5v8

Normal distribution

https://www.youtube.com/watch?v=mtH1fmUVkfE

Normal distributions & Z-scores

https://www.youtube.com/watch?v=mai23vW8uFM

The normal distribution and the 68-95-99.7 rule

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

z-score calculations & percentiles in a normal distribution

https://www.youtube.com/watch?v=_86q-hn_3DQ