We are to read, summarize and critique this particular study entitled:

Hello,

I need help with a homework for cognitive psychology. We are to read, summarize and critique this particular study entitled: "Intuitive Statistics by 8-month old infants" by Fei Xu and Vashti Garcia (link: https://www.pnas.org/content/105/13/5012). We are supposed to summarize the methodology that was used and I am very confused with how the experiment was done. Can you please help? Thank you.