This is known as statistical hypothesis testing. However, to give more confidence in the result of this type of experiment, scientists use statistics to see how likely it is that the result they find is purely by chance. Of course, it is very unlikely that all the acne prone people end up in one group by chance, especially if we have enough people in each group. What if, purely by chance, all the group we selected to eat jelly beans would have had acne anyway while those who didn't eat jelly beans were the lucky sort of people who never get spots? Then, even if jelly beans did not cause acne, we would conclude that jelly beans did cause acne.

There is an element of chance in how many people prone to acne are in each group. Some people will suffer from acne whether they eat jelly beans or not, and some will never have acne even if they do eat jelly beans.

If more people in the group that eat jelly beans have acne, then you might think that jelly beans cause acne. After some time you compare whether the group that eat jelly beans have more acne than those who do not. To do this you could find a group of people and randomly split them into two groups - one group who you get to eat lots of jelly beans and a second group who are banned from eating jelly beans. Let's imagine you are trying to find out if jelly beans cause acne. They find no link, but in the end the real result of this research is bad news reporting!įirst, some basic statistical theory. A girl with a black ponytail comes to Cueball with her claim that jelly beans cause acne, and Cueball then commissions two scientists (a man with goggles and Megan) to do some research on the link between jelly beans and acne.

This comic is about data dredging (aka p-hacking), and the misrepresentation of science and statistics in the media. It was probably a- 'RESEARCH CONFLICTED ON GREEN JELLY BEAN/ACNE LINK MORE STUDY RECOMMENDED!' Title text: So, uh, we did the green study again and got no link.

Data dredging p-hacking