Here is a very interesting graphic I found in Mother Jones magazine.
It is a very good lesson to show clearly that “correlation does not imply causation”. Correlation means that two (or three or more) things happen at the same time. When it gets hot, people stop wearing sweaters. But the common mistake is that people think that one thing causes the other. In our case of temperature, that may be the case. But in many other cases, such as hating sushi and hating gays, some might even say that gay people like sushi, or even that eating raw fish causes people to be gay. But none of that is true. It just happens that people who won’t try sushi also do not accept gay marriage.