1. To choose the correct statistical procedure to test our hypothesis.
2. To correctly interpret the chosen procedure.
3. To choose the correct tabled value (aka critical value) with which to compare your result.
Warning: The Expert says: this section will be difficult and may make little sense unless you have finished both the "look at your data" section and the "state you expectations" section. Additionally, information from those sections will be used later to evaluate your work. I strongly recommend completing these sections if you haven't done so.
To test our hypothesis that children in Samoa are further from their mother than children in Belize, we can perform a statistical test. The test you choose is strongly influenced by what your data looks like and what you want to say about your data (i.e. your hypothesis).