11.1b Range and Outliers

11.1b Range and Outliers

Range - the range of the data set is the largest value minus the lowest value.

• Find the largest number

• Find the smallest number

• subtract the two numbers

Find the range of the data set.

90, 80, 70, 65, 88, 93, 78, 83, 79, 92

• largest number is 93

• smallest number is 65

• 93 - 65 = 28

• The range of value is 28

Find the range of the data set.

5, 3, 4, 8, 8, 7, 9, 9, 10, 7, 9, 9

• largest number is 10

• smallest number is 3

• 10 - 3 = 7

• The range of value is 7

Mean - remember mean is the average of the numbers.

• Add them up.

• divide by total number of values.

Find the mean of the data set

10 5 6 7 8 9 7 8 8 10

• 10+5+6+7+8+9+7+8+8+10=78

• 78 divided by 10 = 7.8

• The mean is 7.8

Outlier - is a value that is much greater or smaller than the other values of the data set.

• Like one person doing super bad in the class.

• Or like only one person got an A while everyone else got a C or below.

• Outliers affect the mean by a lot.

Is there an outlier? If so what is it?

73 75 89 91 87 79 82 83 86 92

• No outlier

• everyone got a A B or C

• so everyone did well

Is there an outlier? If so what is it?

92, 88, 96, 86, 89, 90, 95, 97, 42, 83

• 42 is the outlier

• everyone got a A B except that 42

• so everyone did well except that one person

Multiple Choice

Is there an outlier in the data set?

22, 34, 26, 50, 20, 30, 35, 29, 21, 23

• No

• 21

• 50

Remember we said outliers affect the mean? So we will find the mean with and without the outlier.

In this data set we said 42 is the outlier

92, 88, 96, 86, 89, 90, 95, 97, 42, 83

• Mean with everyone

• (92+88+96+86+89+90+95+97+42+83)/10 = 85.8

• Mean without outlier

• (92+88+96+86+89+90+95+97+83)/9=81.6

• see that one person brought down class average or mean 4%

Multiple Choice

Find the mean. Without the outlier.

5 7 8 9 5 6 8 6 4 32

Hint don't add the 32

Hint 9 total now

• 4.8

• 6.4

• 5.7

• 7.3

So that 32 changed the average alot.

Imagine that data set was weight of a turtle. Most are all small and weigh about 6 pounds. Then we got a HUGE one at 32 pounds. That huge turtle would be the outlier!

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