Lots of journalists, and would-be journalists on their social media feeds, are touting half-baked studies of COVID-19 antibody or RNA prevalence as a reason to choose one pandemic policy over another,

I use Excel 2010 doing my job. and I wonder what is the difference between IRR and XIRR function. NPV and XNPV functions also are mystery. I asked my colleagues some times but no one could explain it clearly.