A sample is a group of items selected from a population. A sample is normally selected because the population is too large or costly to study in its entirety. A population is the entire group of all items that are being studied. Examples of populations may include all registered accountants in Rwanda, all financial institutions in the country and all registered voters in the country. Examples of a sample from the population all accountants registered with CPA Rwanda are a sample from all registered accountants in Rwanda, either banks, or micro-finance institutions are samples of financial institutions in Rwanda.