Estimating the IQ of a LoL challenger player by region
There are 200 challenger players on every server except for CN, which has a superserver instead, which serves as the main sever where the best players play. For the sake of consistency, I’ll estimate the average IQ of the Chinese player on the Ionian server, which is the best and largest Chinese server
Using the statistics I gathered for the pro players:
Size of NA ranked playerbase: 1.2M (average z-score for challenger is 3.82)
Size of EUW ranked playerbase: 3M (average z-score for challenger is 4.05)
Size of KR ranked playerbase: 3.2M (average z-score for challenger is 4.06)
Size of Ionia ranked playerbase: (approx) 1.4M (average z-score for challenger is 3.86)
Assuming racial means of 100 for NA/EUW and 105 for KR/CN, and a correlation of 0.4 between IQ and gaming rank (not skill) yields these estimates:
NA - 123
EUW - 124
KR - 127
Ionia - 126