Bias Unbias sample

To get valid results, a sample must be...

• biased

• unbiased

Tags

CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

The Student Council asked every tenth student in the lunch line how they preferred to be contacted with school news. The results are shown in the table. Is this an unbiased sample? If yes, suppose there are 684 students at the school. How many can be expected to prefer E-mail?

• No, it's a biased sample

• 432

• 304

• 16

Tags

CCSS.7.SP.A.2

You are doing a survey to find out what kids really think about school lunch and you stand outside a lunchroom and ask every 5th person from every grade.

• Biased (Unfair)

• Unbiased (Fair)

Tags

CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

Erick wants to know how many hours of sleep college students get, so he surveys the 12 students in the front row of his college English class.

• Biased

• Unbiased

Tags

CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

Ms. Rolf wants to know the average number of siblings her students have, so she assigns each of her students a number 1-72 and uses a random number generator to survey 12 students.

• Biased

• Unbiased

Tags

CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

Ana wants to know the average student’s opinion of the tardy policy at her school. Which group of students should she survey in order to achieve the most accurate results?

• thirty students who are often tardy
• thirty students who are rarely tardy
• thirty of her friends
• thirty randomly selected students from her school

Tags

CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

A sample should be

• representative of  only middle school students only
• a very large group
• representative of the population
• representative of people who volunteer

Tags

CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

A student was at Hobby Middle school to determine which movie 7th graders preferred: The results are shown below:

-Hunger Games was preferred by 15 students

- Divergent was preferred by 10 students

Based on the results of the survey, how many of the 300, 7th graders would prefer Divergent?

• 75

• 12

• 7.5

• 120

Tags

CCSS.6.RP.A.3B

As a part of a survey, 50 students were asked about their favorite lunch item. The results are shown below.

• Pizza 10
• Tacos 5
• Hot dogs 15
• Hamburgers 20
• 
  

The cafeteria manager knows that about 300 students buy lunch from the cafeteria each day. Based on the table, she predicts that 60 students will buy pizza each day. Which statement about her prediction is true.

• Her prediction is invalid because ⅕ of 50 is 10.

• Her prediction is invalid because ¼ of 300 is 75.

• Her predictions is invalid because 120% of 50 is 60.

• Her predictions is valid 20% of 300 is 60.

Tags

CCSS.6.RP.A.3C

Below shows the number of votes for different sports:

• Football 12
• Basketball 15
• Volleyball 18
• Tennis 5

Based on the information what is the most reasonable prediction for the number of Tennis votes out of the next 50 votes?

• 7

• 15

• 10

• 20

Tags

CCSS.7.RP.A.2C