4 ms·
Salary per annum combines additively, that's fine. £10/yr + £20/yr = £30/yr, easy. When you add 2 annual salaries you're not increasing the number of years tha
by jstanley 6y ago
Salary per annum combines additively, that's fine. £10/yr + £20/yr = £30/yr, easy.
When you add 2 annual salaries you're not increasing the number of years that the salary is paid over.
Death rate per capita does not combine additively, that makes no sense. What would it even mean? 0.1 deaths per capita + 0.2 deaths per capita is not equal to 0.3 deaths per capita because the denominator changes.
- DanBC 6y agoWhy does the denominator change? You're looking at deaths per 100,000 population, and the 100,000 doesn't change for each city. You're doing very simple fraction addition: 1/100,000 + 5/100,000 = 6/100,000
- jstanley 6y agoThe denominator changes because when you look at 2 cities together you don't just add the deaths (numerator), you also add the entire population (denominator). If there are 100,000 people in city 1, with 5 deaths, and 100,000 people in city 2, with 10 deaths, then we have: city 1: 5 deaths per 100,000 city 2: 10 deaths per 100,000 Adding them together, we don't get 15 deaths per 100,000! We get 15 deaths per 200,000 (because they each have 100k residents) = 7.5 deaths per 100,000. I feel like I'm missing the joke here. EDIT: I mean, yeah, literally, if you add the fractions together, you get what you wrote. But that's not a meaningful way to combine death rates.
- DanBC 6y agoSorry, yes, you're right. I'm being dumb.