Below YouTube channel link contains various lectures on Geographical topics as well as Statistical.
https://youtube.com/@anytimelearning-tejvir2079?si=6wlrenaQHhes0eMN
Some of the links are given as under:
1) Statistics and Data:
https://docs.google.com/document/d/1fEOf1F_ylTKtyc57bjzyict0e52wPEiqdkgCjMuLWgM/edit?usp=drivesdk
2) Measures of Dispersion:
https://docs.google.com/document/d/1_z-6o2DQUReXiI8tWD86zeoS-oHsXE4NMMp6RpVilsc/edit?usp=drivesdk