In this investigation, we are going to explore the spread of COVID-19 in Multnomah County. The numbers I am using are based on real data, but due to rounding and other assumptions we must make, it is a hypothetical mathematical exploration more than a scientific or statistical exploration.
In other words, learn from this, but don't cite these numbers in a debate.
We are going to look at weekly data. This seems to make sense because people are infectious for approximately that long. For our purposes there are two things we need to know. First, the number of people who are infectious that week. For simplification, we will call these people carriers. Second, the infection rate, the average number of people each person infects.