I want to get a statistic for the number of cases per person living in urbanised areas I have the number of  cases by country since the beginning of covid. It is simple to plot this against the population to get the cases per capita. But I also  have the population density per square kilometer and the percentage of the population living in urbanised settings. How do I show a plot which takes into account the latter data legitimately?
I have tried (cases to date/((population/100)*percentage of urbanised population)) but I am unsure if this is this legitimate.
 A: It's not clear to me why you are dividing your population by 100, unless you are trying to scale your result to be the number of cases per 100 people living in an urbanized area.  Assuming you are not wanting that, then there is no need to divide your population by 100.
To obtain the number of cases per person living in an urbanized area is a simple calculation that boils down to computing the total number of people living in an urban area and the total number of cases.
To compute the total number of people living in an urban area, you'd simply compute the following:
\begin{eqnarray*}
Total\,Urban\,Population & = & \%\,Urban\,Population\times Total\,Population
\end{eqnarray*}
Once you have this figure, you simply take the total number of cases to date and divide by the Total Urban Population that you computed in the previous step:
\begin{eqnarray*}
Number\,Cases\,Per\,Urban\,Population & = & \frac{Total\,Cases\,to\,Date}{Total\,Urban\,Population}\times100\%
\end{eqnarray*}
That's all there is to it.
