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Samples and Surveys

In this video, we are going to look at samples and surveys. First, lets identify a population. A population is a total group of something that we are going to analyze. For example, if we wanted to see where the high school seniors want to go on a school trip, then the population is high school seniors. Instead of asking every single high school senior, we only want to look at part of the group. This part of the group is called a sample. It would be much easier and more efficient to only interview a percent of the high school seniors. We can safely assume that the opinions of this percentage can represent the high school seniors as a whole if we pick the sample wisely.
Now we will talk about a bias. Different groups of people can have different opinions. If you want a good representation of a group, you want to make sure that you cover the entire group, and not just certain sectors of the group. For example, going back to the high school trip, if you ask the football team where to go on the trip, it would make sense that they would want to see a football game. If you ask the students in theater where they want to go, it would make sense for them to want to see a play. You don’t want to focus the sample on just one group of people. It should represent the entire population. In order to do this, you would want to do random sampling. For example, you might want to ask every fifth student who enters school. You do not want to just ask the students at the gym, or at the library, or in theater. Not every student may go to the gym, or be in the library, or be in theater, but every student must enter school, so this method would best represent the population as a whole.