Hypothesis testing is one of the most confusing and frustrating areas of mathematics. Here are some terms you need to know:
Sample
A portion of the population that you gather information from. A good sample is one that represents the population accurately.
Census
A census is when you gather information from the entire population.
Survey
A survey is the act of gathering information from a sample.
Parameter
A parameter is a characteristic of the population, such as the number of people with brown hair.
Statistic
A statistic is a characteristic calculated from a sample, such as the number of brown haired people within a sample.