Vocabulary
A sample in which every member of the population has an equal chance of being selected
Random Sampling
The teachers in a school are asked to send four students from their homerooms to represent the class. Mr. Burts puts the names of all the students in a box, mixes the names, and pulls out four names without looking. Is this bias?
. Is this biased or unbiased?
NO
Mr. Burr’s method creates a random sample.
A survey company is trying to determine if people in a certain state think that pollution is too high.
Which choice BEST represents the population?
a. Every person who owns more than 2 cars.
b. All the people who live in wealthy neighborhoods.
c. All the people who live in dirty neighborhoods.
d. Every person that lives in the state.
d. Every person that lives in the state.
A life guard wants to know the average time it takes to swim 75 yards. There are an average of 645 swimmers in the lap pool each year. How can he find a reasonable estimate for the amount of time it takes to swim 75 yards?
A. time any swimmer in the lap pool and use that time
B. time himself on the swimming and use that time
C. time 50 swimmers and average their times
D. time 5 swimmers and average their time
C. time 50 swimmers and average their times
When information is being gathered about a group, the entire group of objects or individuals considered for a survey
Population
Mr. Gillespie wants to know the favorite type of music of the students at his school. He decides to ask every third student who enters the building. Is bias or representative?
Representative
A gaming website wanted to find out which console its visitors owned. Which choice best represents a population?
A. Visitors to the 3DS section.
B. All of the website visitors.
C. Visitors to the PS4 section.
D. Visitors who are on the website for more than 5 minutes.
B. All of the website visitors.
Mark wants to know how many of his company’s 1,500 employees take Uber to work. He asks every fifth employee out of 500 entering the building. Which statements are true?
Select all the true statements.
A. The sample is biased.
B. The sampling method is not random.
C. The population is all the company’s employees.
D. The sample is representative of the population.
C. The population is all the company’s employees.
D. The sample is representative of the population.
When a sample does not accurately represent the population
Biased
In the last meeting, 75% of the employees were in favor of adding a day care service in the building and 25% were against it. The manager creates random samples of the employees using the numbers 1 to 24. Which range of numbers can the manager use to represent the employees who were against adding a new day care service?
A. 16 to 24 C. 19 to 24
B. 6 to 24 D. 1 to 24
C. 19 to 24
A beverage company wanted to see if people in the United States liked their new logo. Which choice best represents a population?
A. A selection of logo artists.
B. Every person in the United States.
C. A selection of shoppers from different states.
D. 3,800 children age 5 - 15
C. A selection of shoppers from different states.
A musician wants to determine what the people who bought his last album thought about the songs.
Which choice BEST represents a sample?
a. Every person who bought the album.
b. A selection of 250 people who bought the album.
c. A selection of 250 people who didn't buy the album
b. A selection of 250 people who bought the album.
Remember that a population data set contains all members of a specified group. A sample data set contains a part, or a subset, of a population.
A part of the population that is chosen to represent the entire group
Sample
A survey is conducted at the local shopping mall about household products used on a daily basis. Is this sample bias or representative?
Biased, only customers at the shopping mall have an opportunity to be surveyed
A mayor wanted to see if the people in his town thought he was doing a good job. Which choice best represents a sample?
A. 1,000 unemployed voters.
B. The mayor's family.
C. The residents of the town.
D. 242 voters.
D. 242 voters.
There are 1000 pipes in stock at Patty’s hardware store. She randomly selects 60 pipes and finds that 6 of the pipes are made of plastic. How many pipes in stock at her store can Patty predict are made of plastic?
100 pipes are predicted to be made of plastic.
A representative sample is a sample that has the same characteristics as the population.
Representative Sample
A shirt manufacturer wants to check quality control of their products. The plant manager decides to check every 5th shirt inspected by Inspector Gadget. There are 15 inspectors in the plant. Is this sample bias or representative?
Biased, only Inspector Gadget's shirts are being checked
You have a jar filled with skittles and 10 skittles were on the table. Which one is the population: the jar filled with skittles or the skittles on the table?
The jar filled with skittles
A librarian is interested in the numbers of books that visitors check out from the library. She examines the checkout records of 250 randomly selected adult visitors.
Identify the population and sample for this situation.
A. The population is all visitors of the library; the sample is the adult visitors of the library
B. The population is all adult visitors of the library; the sample is the 250 visitors selected.
C. The population is all visitors who check out at least 1 book from the library; the sample is the 250 visitors selected.
D. The population is the 250 visitors selected; the sample is the 250 visitors who check out at least 1 book from the library.
B. The population is all adult visitors of the library; the sample is the 250 visitors selected.
Remember, the population is the entire group of people or things to be studied. The sample is part of the population.