Using Random Samples to Describe Population

Population Sampling

EOG Review SP.1

In this lesson you will learn how to collect data about a population by identifying a sample of the population.

Population

The ENTIRE group of people or object from which data is taken

Sample

The PART of the population from which data is actually collected.

Random Sample

From a population is a sample that is selected in a way that gives every different possible sample of the same size an equal chance of being the sample selected.

Representative

Sample is a sample that has a distribution that closely resembles the population distribution in center, shape, and spread.

Bias

Is a systematic (built-in) error which makes all measurements wrong by a certain amount.

Unbiased

Fair, equitable, and impartial.

Inference

Is the process of drawing conclusions (Prediction) about an underlying population based on a sample.

Sampling the Population

How Many Games?

Lin wants to know how many games teenagers in the US have on their phones

• What is the population for Lin's question?

• All people who are 13 to 19 years old in the United States who have a phone.

• Explain why collecting data for this population would be difficult.

• There are too many people to collect data from everyone. It would take too much time, energy, and money to collect the data.

• Give an example of a sample Lin could use to help answer her question.

Multiple Select

Suppose you are interested in learning about how much time seventh grade students at your school spend outdoors on a typical school day.

Select all the samples that are a part of the population you are interested in.

• The 20 students in a seventh grade math class.

• The first 20 students to arrive at school on a particular day.

• The seventh grade students participating in a science fair put on by the four middle schools in a school district.

• The 10 seventh graders on the school soccer team.

• The students on the school debate team.

Open Ended

When the groups become too large, how can we obtain some data to begin answering a question about the group?

Open Ended

What are some drawbacks of using samples instead of the entire population?

Open Ended

What are some reasons samples are necessary?

Multiple Choice

Daisy wants to know what breed of dog is most popular as a pet in her state. What is a sample that could be used?

• A few cat owners from each of the major cities in the state.

• A few dog owners from each of the major cities in the state.

• A few dog owners from the dog park across town.

• A few dog owners from Daisy's neighborhood.