Researchers asked questions in 1001 randomly selected adults in Russia. We found a statistically significant, strong positive correlation between income and the number of recycling bins filled their houses per week (r = 0,77). Choose the best interpretation of the result.

 
1. The sample is too small to allow us to draw any conclusions about the relationship between income and recycling in Russia.

2. We can not conclude that economic comfort causes more recycling because this type of research design does not allow us to infer a causal relationship.

3. The results show that the highest income affects people so as to recycle more than those with lower income.

Correlation does not necessarily indicate causation.