Selecting the sample size
This raises a dilemma. How many children do we actually need as a bare minimum to ensure a meaningful result? Amazingly, this can actually be calculated scientifically to an extraordinary degree of accuracy, however in the case of children being corrupted by video games, it is also extraordinarily difficult to acquire the information we need to make this calculation in the first place, leading to a catch-22 situation.
If we know the ‘average’ (or ‘mean’) aggression level of the entire population, and the ‘standard deviation’ of aggression in the population – which is a fancy way of saying roughly how much people’s aggression levels differ at the most from person to person, excluding extreme cases – we can calculate the minimum number of children we would need to test to get a scientifically significant result.
Unfortunately, it is not possible to precisely know these figures, however one way to approximate is to take a large generalized cross-section of the population (selection method 2 above), give them the same aggression test we would give the children after exposing them to video games, assigning each person an aggression level and extrapolating the figures to cover the entire population of the country or world as desired (if the sample is all taken from one country, you can only extrapolate it to cover that country; to cover the world you have to test subjects from a large group of randomly selected countries).
If you are confused, think about exit polls during an election. Simplifying, we ask people at random as they leave the voting booth who they voted for. If we have asked 10,000 people and 40% of them voted for the conservative party, and the population of the electorate is 50 million, then we can guestimate that 50,000,000 * 40% = 20 million people will vote conservative. As the number of people we survey at the exit poll goes up, so the estimation becomes more accurate.
How does this translate to kids? Well, this is analogous to seeing if a particular group of children would vote differently to the general population. You can think of ‘particular group’ as ‘those exposed to video games’ and ‘vote differently’ to ‘become more aggressive’. Once we’ve gathered some data from the general population at the exit poll, we can calculate how many children we’ll need to expose to video games in order to test if they have a significantly different voting response to the population.
(Statisticians: I’m aware this comparison has flaws regarding discrete measurements and uncorrelated sample sets; I’m trying to keep it simple, the principle holds)
In a nutshell, if we don’t test enough children, we can’t draw a statistically significant result from the experiment, and right now, we don’t know what the minimum number of children needed actually is.