Misleading Data and Biased Samples

A sample is...

• The group of people you survey to collect data

• The entire group of people you want to learn about

• Free food

A biased sample...

• Is valid

• Favors one or more parts of the population over others

• Accurately represents the entire population

Is the survey biased or unbiased?

Each student's name is written on a piece of paper. The names are placed in a bowl, and names are picked without looking.

• Biased

• Unbiased

Which graph should be used if...

You want to show that ticket sales have risen, but it's not that big of a deal.

• Graph A

• Graph B

A computer science teacher wants to know how often students at a school access the Internet. The teacher uses a sample of students from one of her computer classes.

• Biased

• Unbiased

True or False: ALL samples lead to a good prediction about an entire population?

• True

• False

If I asked parents at a basketball game if they liked basketball, would this be a biased or unbiased sample?

• Unbiased

• Biased

• the residents

• the officers

• the mailman

Decide whether the sampling method could result in a biased sample:

On the first day of school, all of the incoming freshmen attend an orientation program. Afterward, the principal wants to learn the opinions of the freshmen regarding the orientation. She decides to ask 25 freshmen as they leave the auditorium to complete a questionnaire

• biased

• not biased

Identify the population:

A quality control inspector at a computer assembly plant needs to estimate the number of defective computers in a group of 250 computers. He tests 25 randomly chosen computers

• assembly plant

• the control inspector

• the computers