Sol is investigating birth rates in different countries. He thinks that European countries have the lowest birth rates.
Write a possible hypothesis for Sol to use in his investigation.

A hypothesis is a precise, testable statement of what the researcher predicts will be the outcome of the study. Sol's initial thought is that "European countries have the lowest birth rates". To make this a formal hypothesis, it needs to be more specific and comparative. A good hypothesis would be: "The average birth rate in European countries is lower than the average birth rate in non-European countries." This is testable because you can collect data on birth rates, calculate the average for European and non-European countries, and then compare the two averages.