I am currently looking into a dataset, and have a question about calculating average.
Assume I have the following data of the number of dogs in four different cities over the course of 4 weeks:
London NYC Berlin Tokyo mon1 2 4 2 2 tue1 3 5 10 2 .... sat4 3 3 1 1 sun4 2 4 2 3
Now, I try to calculate the average number of dogs in each city.
Why do I get a different average if I calculate average for all four weeks at once (e.g. average(mon1:sun4)), compared to if I calculate the average for each week, and then find the total average from there?
For instance, if calculating the entire average all at once, I London stands out as having the highest average, whereas if I calculate the average for each week, and then find the total average from there, Berlin has the highest average.
Furthermore; what is the "correct" average?