system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: In statistics, why can't you sample a group larger than 10% of the whole?

I've been told that taking a sample larger than 10% of the population will be less accurate than say, taking a sample of 50% of the population. How does this work? To me it seems that, the more people you sample, the more accurate the study will be.
gpt
there is a certain ratio of cost to reliability. in theory it would be best to make a study on the whole population. but since that is near impossible and at least very costly we use samples. and there is a certain minimum sample you need for the sake of accuracy. depending on the size of population, method of picking for sample and so on, you achieve a number that is the minimum. A bigger sample should be more accurate, the closer you get to the number of all of the population.. You will usually go with somewhere close to the minimum (not less, sometimes slightly more) because of cost.