Did you know that the US spending on science is causing suicides?
Well, not really, if you apply common sense. Just because the trends are similar, it does not mean that one causes another, just as good grades at school tell nothing about your intelligence. Check out other bizarre correlations here.
Nevertheless, by putting two variables on a scatter plot, we can see if there are some relationships and how strong they are. Say - human age and height is increasing over time in most of the cases so we will see a quite strong correlation there.
A strong correlation is represented by the correlation coefficient, a number that quantifies some type of correlation and dependence, meaning statistical relationships between two or more random variables or observed data values. A strong correlation is closer to 1. Weak to 0.
Here is a geeky game called “ Guess the correlation”. Can you tell the coefficient?