Biased Samples & Misleading Data

Biased Samples & Misleading Data

Lessons 10-2 & 10-3

Multiple Choice

A sample is...

• The group of people you survey to collect data

• The entire group of people you want to learn about

• Free food

Multiple Choice

A biased sample...

• Is valid

• Favors one or more parts of the population over others

• Accurately represents the entire population

​Maci surveyed all of the members of her Softball team about their favorite sport.​

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Based on these results, Maci concludes that softball is the favorite sport ​among ALL of her classmates.​

Open Ended

Why is Maci's survey biased?

Multiple Choice

Is the survey biased or unbiased?

To represent all students attending a school, the principal surveys the students in one math class.

• Biased

• Unbiased

Multiple Choice

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

Multiple Choice

Is the survey biased or unbiased?

Every 20th person is chosen from an alphabetical list of all students attending a school.

• Biased

• Unbiased

Multiple Choice

Is the survey biased or unbiased?

Customers at a music store are surveyed about what they like to do in their free time.

• Biased

• Unbiased

Misleading Graphs & Statistics

​Even if the data is unbiased, graphs and statistics can still be used to ​influence your opinions.

Poll

Which graph appears to show a steeper increase in price?

• Graph A

• Graph B

Multiple Choice

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

Multiple Choice

Which graph should be used if...

You want to tell people that ticket sales keep going up, and it's ridiculous!

• Graph A

• Graph B

Multiple Choice

Which graph should be used if...

You want people to think that your business is extremely profitable.

• Graph A

• Graph B

That may be true, but that's only because Tornado is SO much taller than all the others!​

​

The Median would be a more accurate "average" for this data.​

​

"The average height of our roller coasters is 170 ft!"

​

Multiple Choice

To find the _________ you add up all the numbers and then divide by how many numbers you have.

• Mean

• Median

• Mode

• Range

Multiple Choice

Find the Mean of:
8, 14, 32, 6, 15

• 15

• 175

• 75

• 12

Multiple Choice

To find the ________ you put all numbers in order from least to greatest and find the number that is in the middle.

• Mean

• Median

• Mode

• Range

Multiple Choice

Find the median of these numbers:
4,2,7,4,3

• 2

• 5

• 7

• 4

Multiple Choice

A data set can have more than one mode

• True

• False

Multiple Choice

What is the mode of the data below?

12 , 14 , 5 , 12 , 5 , 12 , 11

• 5

• 12

• 5 and 12

• 11.8

Multiple Choice

The mode score on the 7th grade math test was 94! Which of these interpretations must be correct?

• 99 was the highest score on the test.

• More students received a 94 than any other score

• No student scored below a 50

• A score of 91 was slightly below average.