Representative Sampling

A good sample must be: representative and random.

(Watch Mr. Jackson's video for help)

Which picture shows a representative sample?

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Sameer surveys 15 students in his class to get ideas for his science project. What is the population?

• All students at Commodore

• All students in Sameer's class

• The 15 people who get picked

• All people in the world

To find out what sort of events they should plan, the student government officers at Truth send a survey to 30 students whose names were randomly selected. The sample is...

• The 30 students who were sent the survey

• All students at Truth

• The student government officers

An employer wants to know how their 500 employees like working for them. Which is the most representative sample?

• Ask the first 75 people to show up for work

• Randomly select the names of 10 employees

• Poll the Employees of the Month for the past year

• Randomly select the names of 75 employees

Andre wants to survey a random sample of the student body in his school to find out which day after school would work best for students to do volunteer work for a local charity. Which sample would best represent the student body?

• asking twenty students waiting in line for lunch

• asking twenty students on their way to the bus after school

• asking one person from the seventh grade daily for twenty days

• asking one person each from twenty different classrooms during the first class period

Which statement best describes a random sample of all students in a middle school?

• Of all the students who are on the track team, the first three to finish a race are selected.

• Of all the students who are in the drama club, every third student on the roster is selected.

• Of all the students who complete an assignment, the first, third, and tenth students are selected.

• Of all the students who attend a school-wide assembly, those sitting in every third seat are selected.

Four candidates are running for school president. A random sample of students at the school are surveyed about which of the candidates they are likely to choose. The chart above shows the number of students from the random sample who chose each candidate. A total of 800 students are expected to vote in the election for school president. Based on the information shown in the chart, which election outcome is most likely?

• Rasheed will win with 192 votes.

• Rasheed will win with 189 more votes than he had in the survey

• Janelle will win with 8 more votes than the second-place finisher, Rasheed.

• Janelle will win with 128 more votes than the second-place finisher, Rasheed

Susan polled 587 people throughout each city in her county.  Each city is the same size.  Is this sample of the residents of cities in the county likely to be biased?

• yes

• no