[andrew_n]

Yes, and the medical professionals dealing with this are getting statistics about diagnosis and recovery rates and times by analyzing case histories, not applying estimation formulas to totals.

Data gets aggregated and used in mathematical models that can predict outcomes in various hypothetical scenarios, but given that this is a real-world situation, the professionals are going to be looking at the actual data first to find out what’s happening. They can directly answer questions such as, of the patients diagnosed 1 week ago, what’s their status today?

Anyone looking at only total numbers of cases per day simply doesn’t have the data required to compute the things they’re trying to compute with much accuracy. It’s possible to produce estimates with confidence intervals based on sensitivity analysis, but nobody doing that with any care using aggregate data is going to come out with a number as high as 20% for a lower bound. Given that N=6 is a guess, the range reported should be bounded by plugging in plausible extreme values for your guess of N, not assuming your guess of N=6 is exactly correct.