At 3-4% fatality rate? Must be US made.
Closer to what mate? According to the recent stats at 181k confirmed cases and 7k deaths, it's less than 4%. However, according to scientists, the number of infected people is waay higher than official numbers. What's your point exactly?
The second main method to calculate it is death/(death+cured). Pick whichever one you prefer.
'The virus is asymptomatic for 2 weeks' Where did you get this info from?
No, it's not common knowledge, just give us your source or shut the fuck up. You are making shit up.
Idk, 'Conclusion:
This work provides additional evidence for a median incubation period for COVID-19 of approximately 5 days, similar to SARS.' (https://annals.org/aim/fullarticle/2762808/incubation-period-coronavirus-disease-2019-covid-19-from-publicly-reported)
Also, a doubling time of 6 days? Where did you see that? According to this https://www.worldometers.info/coronavirus/country/italy/ the doubling time seems to be faster?