Population&Sample
Determine whether the data are collected from a population or a sample:
A survey of 400 high school sophomores at a school with 842 sophomores
Survey
You list all the counties in Pennsylvania and choose every third county.
Systematic
Determine whether the following is a population or a sample:
The address of every student in the school
population
Identify the type of sample and explain why the sample is biased:
A town council wants to know whether residents support lower taxes for those who own waterfront property. 34 owners of waterfront property are surveyed
Cluster: The cluster was not randomly selected. people who own waterfront property will support lower taxes for those who own waterfront property.
Determine whether the data are collected from a population or a sample:
the number of people 65 or older in the United States
Population
You distribute questionnaires in the cafeteria and use only the questionnaires that are returned.
Self-selected
Determine whether the following is a population or a sample:
A survey of 80 people who access a website
sample
Identify the type of sample and explain why the sample is biased:
A local radio station is considering switching from country music to classical music. Randomly throughout the day it announces the phone number and website where listeners can go to place their vote for either country music or classical music.
self-select: Those who are listening to the station probably prefer country music, so they are more likely to vote for country music.
Identify the population and sample:
In the United States, a survey of 5000 high school seniors found that 3284 of them plan on attending a 4 year university following graduation.
Population: All High school seniors in the US
Sample: 500 high school seniors in the survey
A student researcher records whether people at a restaurant leave a tip for the server.
observational
Determine whether the numerical value is a parameter or a statistic:
34% of the surveyed hockey players first played hockey before their 10th birthday
statistic
Identify the type of sample and explain why the sample is biased:
A local senator is proposing a bill to lower the limit on the number of lobster that can be bought each day. Participants in a local fishing tournament are asked to complete a survey.
biased; Local fisherman are not likely to support the bill, because they would probably want to catch as much lobster as possible.
Identify the population and sample:
In a school district, a survey of 1000 middle school students found that 894 of them participate in an extracurricular activity.
Population: All middle school students in the school district
Sample: 1000 middle school students in the survey
You randomly select four students from each table in the cafeteria.
stratified
Determine whether the numerical value is a parameter or a statistic:
82% of all the tickets sold were for the Saturday matinee
parameter
Identify the type of sample and explain why the sample is biased:
A triathlon organizer wants to know if a Saturday morning triathlon is preferred over a Sunday morning triathlon. The organizer randomly surveys five triathletes in one of the age groups.
Cluster; only one age group was surveyed.
Identify the population and sample:
In the US, a survey of 2500 homeowners with a monthly mortgage payment found that 1280 of them have refinanced their mortgage within the last five years.
Sample: 2500 homeowners in the survey
You divide all the students at a university into commuting students and campus-dwelling students, and then you randomly select all the students from the commuting group.
Cluster
Determine whether the numerical value is a parameter or a statistic:
The CHS yearbook staff found that 72% of surveyed students prefer burgers over pizza for lunch.
statistic
Explain why the survey question may be biased:
"Our plant has not been making a profit. Do you agree that the company should close this plant?"
Possible Answer: People may hesitate to vocalize their agreement if the are standing next to employees at the plant. This question would be better asked anonymously.