Descriptive Statistics

1
Descriptive Statistics

• Measures of Skewness Kurtosis

2
Descriptive Statistics

• Measures of Central Tendency
• Mo
• Mdn.
• Mean
• Measures of Variability
• Range
• Semi-Interquartile Range
• Average Deviation
• Standard Deviation
• Measures of Skewness Kurtosis

3
Skewness Negative Skewness
4
Skewness Positive Skewness
5
Descriptive Statistics

• Measures based on Quartiles
• Q3-Q2lt Q2-Q1Neg skewness
• Q3-Q2gt Q2-Q1Pos Skewness
• Pearsonian Measure of Skewness

1 Pos 0 Norm -1 Neg
6
Measures of Skewness

• Measures based upon the third moment around the
  Mean.

7
Measures of Skewness

• Measures based upon the third moment around the
  Mean.

-1 Negative 0 Normal 1 Positive
8
Descriptive Statistics

• Measures of Skewness
• Pearsonian Measure of Skewness
• Measures Based on 3rd Quartile
• Measures of Kurtosis
• Kurtosis is a measure of the flatness or
  peakedness of a Distribution
• Normal Kurtosis - Mesokurtic
• Flat Kurtosis - Platokurtic
• Peaked Kurtosis - Leptokurtic
• A Measure of Kurtosis based on the 4th moment
  about the Mean

If less then 0 PlatokurticMore than 0
LeptokurticIf 0 then Mesokurtic
9
Descriptive Statistics
14-Feb-97

• The first test will cover material up to this
  point!!