Finding Outliers

Given the 5 number summary, the maximum is an outlier.

• True

• False

Given the 5 number summary, the minimum is an outlier.

• True

• False

Does the data below have outliers?

74, 88, 78, 90, 94, 90, 84, 90, 98, 80

Desmos:

1. Row 1: Type the data list into Desmos:

Type L = [ data separated by commas]

2. Row 2: Type: stats(L)

3. Row 3: Type the values for Q3 and Q1 into the formula Q3 - Q1 to find the IQR

4. Row 4: Type the values for Q1 and the IQR into the Left Fence Formula: Q1 - 1.5(IQR) to find the value of the Left Fence. If there are any data values LOWER than the Left Fence, there is an outlier.

5. Row 5: Type the values for Q3 and the IQR into the Right Fence Formula: Q3 + 1.5(IQR) to find the value of the Right Fence. If there are any data values HIGHER than the Right Fence, there is an outlier.

• Yes

• No

List all of the outliers of the data set:

38, 42, 77, 47, 74, 51, 48, 41, 82, 72, 74, 129

Desmos:

1. Row 1: Type the data list into Desmos:

Type L = [ data separated by commas]

2. Row 2: Type: stats(L)

3. Row 3: Type the values for Q3 and Q1 into the formula Q3 - Q1 to find the IQR

4. Row 4: Type the values for Q1 and the IQR into the Left Fence Formula: Q1 - 1.5(IQR) to find the value of the Left Fence. Data values LOWER than the Left Fence are outliers.

5. Row 5: Type the values for Q3 and the IQR into the Right Fence Formula: Q3 + 1.5(IQR) to find the value of the Right Fence. Data values HIGHER than the Right Fence are outliers.

• 38

• 38 and 42

• 82 and 129

• 129

Identify all of the outliers of this data set:

74, 63, 69, 62, 33, 79, 70, 60, 107, 119

Desmos:

Row 1: Type the data list into Desmos:

Type L = [ data separated by commas]

Row 2: Type: stats(L)

Row 3: Type the values for Q3 and Q1 into the formula Q3 - Q1 to find the IQR

Row 4: Type the values for Q1 and the IQR into the Left Fence Formula: Q1 - 1.5(IQR) to find the value of the Left Fence. Data values LOWER than the Left Fence are outliers.

Row 5: Type the values for Q3 and the IQR into the Right Fence Formula: Q3 + 1.5(IQR) to find the value of the Right Fence. Data values HIGHER than the Right Fence are outliers.

• 33

• 33, 119

• 33, 107, 119

• 119

Identify all of the outliers of this data set:

107, 92, 111, 119, 99, 100, 89, 94, 125, 93

Desmos:

1. Row 1: Type the data list into Desmos:

Type L = [ data separated by commas]

2. Row 2: Type: stats(L)

3. Row 3: Type the values for Q3 and Q1 into the formula Q3 - Q1 to find the IQR

4. Row 4: Type the values for Q1 and the IQR into the Left Fence Formula: Q1 - 1.5(IQR) to find the value of the Left Fence. Data values LOWER than the Left Fence are outliers.

5. Row 5: Type the values for Q3 and the IQR into the Right Fence Formula: Q3 + 1.5(IQR) to find the value of the Right Fence. Data values HIGHER than the Right Fence are outliers.

• 66

• 89

• 66 and 89

• 125

Identify all of the outliers of this data set:

20, 52, 86, 80, 44, 49, 57, 41, 44, 55

Desmos:

1. Row 1: Type the data list into Desmos:

Type L = [ data separated by commas]

2. Row 2: Type: stats(L)

3. Row 3: Type the values for Q3 and Q1 into the formula Q3 - Q1 to find the IQR

4. Row 4: Type the values for Q1 and the IQR into the Left Fence Formula: Q1 - 1.5(IQR) to find the value of the Left Fence. Data values LOWER than the Left Fence are outliers.

5. Row 5: Type the values for Q3 and the IQR into the Right Fence Formula: Q3 + 1.5(IQR) to find the value of the Right Fence. Data values HIGHER than the Right Fence are outliers.

• 20, 24.5, 76.5, 80, 86

• 24.5 and 76.5

• 20, 80 and 86

• 57

Identify all of the outliers of this data set:

18, 68, 15, 45, 46, 36, 72, 34, 42, 38

Desmos:

1. Row 1: Type the data list into Desmos:

Type L = [ data separated by commas]

2. Row 2: Type: stats(L)

3. Row 3: Type the values for Q3 and Q1 into the formula Q3 - Q1 to find the IQR

4. Row 4: Type the values for Q1 and the IQR into the Left Fence Formula: Q1 - 1.5(IQR) to find the value of the Left Fence. Data values LOWER than the Left Fence are outliers.

5. Row 5: Type the values for Q3 and the IQR into the Right Fence Formula: Q3 + 1.5(IQR) to find the value of the Right Fence. Data values HIGHER than the Right Fence are outliers.

• 16 and 64

• 15, 68,72

• 15,16,64,68,72

• 72

Identify all of the outliers of this data set:

22, 26, 31, 37, 31, 26, 50, 28, 24

Desmos:

1. Row 1: Type the data list into Desmos:

Type L = [ data separated by commas]

2. Row 2: Type: stats(L)

3. Row 3: Type the values for Q3 and Q1 into the formula Q3 - Q1 to find the IQR

4. Row 4: Type the values for Q1 and the IQR into the Left Fence Formula: Q1 - 1.5(IQR) to find the value of the Left Fence. Data values LOWER than the Left Fence are outliers.

5. Row 5: Type the values for Q3 and the IQR into the Right Fence Formula: Q3 + 1.5(IQR) to find the value of the Right Fence. Data values Higher than the Right Fence are outliers.

• 11.5

• 11.5, 47.5, 50

• 47.5,50

• 50

A value that is much higher or much lower than the other values in a set of data.

• Outlier

• Box Plot

• Range

• Histogram