Percentiles
https://davidwills.us/stat200/percentiles.html

Paste the Chicago commutes into Percentiles

                this percentile:
25%ile=_______    AKA:____
50%ile=_______    AKA:____    AKA:______
75%ile=_______    AKA:____

0%ile=_____      AKA:____
99%ile=_____     AKA:____

15 is at what percentile:_____
The next number in the data set is 20, what percentile is it at:______
How many 15's are in the data set:_____
When there's not many numbers or there is a lot of duplicate values, 
percentiles are fuzzy/confusing. The data is (trying) to be divided into
100 -iles.


Generate a data set of 1000 whole numbers normally distributed with mean 500 and SD 100.
https://davidwills.us/math103/distro_generator.html

Copy and paste into Percentiles page.
With 1000 numbers, each one percentile is about 10 numbers.
Some percentiles might be fictitious numbers.

25%ile=_______    AKA:____
50%ile=_______    AKA:____    AKA:______
75%ile=_______    AKA:____

0%ile=_____      AKA:____
99%ile=_____     What is the max value of this data:______   Ah-ha! So try
99.9%ile=______

One SD above the mean is ~600. What is 600's percentile:_______
One SD below the mean is ~400. What is 400's percentile:_______
(If your data does not contain either of those numbers, try 599 or 601, 399 or 401...)
Of this normally distributed data, how much is within one SD of the mean:_____%
The empirical rule says 68% of normal data is +-1 SD of the mean.

Two SDs above the mean is ~700. What is 700's percentile:_______
Two SDs below the mean is ~300. What is 300's percentile:_______
(If your data does not contain either of those numbers, try 699 or 701, 299 or 301...)
Of this normally distributed data, how much is within two SDs of the mean:_____%
The empirical rule says 95% of normal data is +-2 SD of the mean.