>>513658732 (OP)
Likely not accurate at all. It's not common for guys to get their test levels checked. So there would need to be a study specifically to collect this info. And then you deal with dishonest governments paying for skewed studies, like we see with the Chinese IQ data, obviously taken from averages of affluent Chinese only.
Also there is no source provided to the studies that gathered this info, but almost certainly there was a different study sourced for each nation. You can't aggregate data across different studies because the methods are always different, even if slightly. You don't want to imply the same conditions for every single study when it's not the case. I highly doubt nations like Mongolia, Ethiopia, Pakistan, Russia, India, et. al. all worked together to perform the exact same study using the same method and demographic sampling.
That said, a nation like Mongolia at the top does make sense, as does India at the bottom. But that doesn't mean this tweet is true either.
