1. Descriptive Statistics Measures of Skewness & Kurtosis

2. Descriptive Statistics u Measures of Central Tendency Mo Mdn. Mean u Measures of Variability Range Semi-Interquartile Range Average Deviation Standard Deviation u Measures of Skewness & Kurtosis

3. Skewness: Negative Skewness

4. Skewness: Positive Skewness

5. Descriptive Statistics u Measures based on Quartiles Q 3 -Q 2 < Q 2 -Q 1 =Neg skewness Q 3 -Q 2 > Q 2 -Q 1 =Pos Skewness Pearsonian Measure of Skewness +1 Pos 0 Norm -1 Neg

6. Measures of Skewness u Measures based upon the third moment around the Mean. A Moment is a Deviation Score Raised to some POWER

7. Measures of Skewness u Measures based upon the third moment around the Mean. -1 Negative 0 Normal +1 Positive

8. Descriptive Statistics u Measures of Skewness Pearsonian Measure of Skewness Measures Based on 3rd Quartile u 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 = Platokurtic More than 0 = Leptokurtic If 0 then = Mesokurtic

9. Descriptive Statistics The first test will cover material up to this point!! 14-Feb-97