I have doubts. I use data on electricity consumption per capita (per year) from 1960-2014. The sample size in this case is N = 55 for the whole world, as well as for individual regions and countries. However, the annual per capita consumption of electricity for the world covers approximately 7,000,000,000 people, and for Norway, for example, about 5 million, but in both cases for the period from 1960 to 2014, N = 55. Is there a way to statistically evaluate the fact that in the first case the population of 7 billion people is included, and in the second much less, in terms of reduction of confounding and bias?
Maybe the question is not clear. I will try to clarify. This is about the statistical analysis of time series. The period from 1960 to 2014 covers 55 years. Thus, the sample size is N = 55 for all countries and regions. Population size (number of people) is not reflected in sample size in time series (number of years). When calculating the p value in this case, it does not matter whether the research covers 1000 people, or a million, or a billion, the width of the sample is always 55. It is illogical to me, but mathematically it is so.