Bias ?

Why do we randomly select our samples?

• to control every aspect

• reduce bias

• so we don't get the same answers from everyone

• because it is easier to do

Why do we randomly select our samples?

• to control every aspect

• reduce bias

• so we don't get the same answers from everyone

• because it is easier to do

Leslie surveyed the 9 youngest students in the elementary school. Is this sample likely to be representative of all the students in the school?

• yes

• no

Dylan wants to know how the students at his school rate the cafeteria. He asked his school's basketball team to rate the cafeteria. Is this a biased sample of the school's population?

• Yes, because it only includes one group of people.

• No, the basketball team has the smartest students

• Yes, because it's voluntary survey

• No, he should have asked the football team

Determine if the following study is biased.

A public library asked every 10th person who entered to name the type of book they were getting.

• A. Biased

• B. Unbiased

Determine if the following study is biased.

Carlos wants to know the favorite sport of people at his school so he asks his baseball team.

• A. Biased

• B. Unbiased

Determine if the following study is biased.

A company makes DVDs and randomly selects 25 from 1500 to test them to see if they work.

• Biased

• Unbiased

Determine if the following study is biased.

A hospital wants to open a gym. They ask the night-shift ER staff if they would use the gym.

• Biased

• Unbiased

Is this question biased or fair?

"Do you think bike helmets should be mandatory for all bike riders?"

• biased

• fair

Is this question biased or fair?

"Do you prefer the natural beauty of hardwood floors over outdated laminate?"

• biased

• fair