11.4 Standard Deviation

11.4 Standard Deviation

What is Standard Deviation?

• Standard deviation tells us how much the data varies from the average

• A small standard deviation means the data is very close to the mean

• A large standard deviation means the data can be very far away from the mean

Sometimes the mean doesn't give us the whole story

• My age is 30, my husband is 29, and my daughter is 2

• The mean age of people in my house is 20.3

• Does that accurately represent the ages of people in my house?

• What would you guess about the standard deviation?

Fun fact!

• This is the formula for calculating standard deviation...

• ...but...

• ...You don't have to calculate it!

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Multiple Choice

Both batters have the same average distance. Which one has a greater standard deviation?

• Batter A

• Batter B

• They have about the same standard deviation

Multiple Choice

Which golfer is more likely to hit the ball 320 yards?

• Golfer A

• Golfer B

Multiple Choice

Which sales person is more likely to sell 6 cars in a month?

• Sales person A

• Sales person B