1. Basic Data Analysis: Descriptive Statistics

2. Types of Statistical Analysis n Descriptive n Inferential: u Test of Differences u Test of Associative u Predictive

3. Pre Descriptive Statistics n Data entry - Data coding (data code book). n Data matrix n Descriptive statistics - “describe” the data, portray an average respondent (data reduction): u Summarizes u Conceptualizes u Communication u Interpolation/extrapolation

4. Descriptive Statistics n Statistical concepts: u Measures of Central Tendency u Measures of Variability u Other Descriptive Measures

5. Measures of Central Tendency n Applies to any measure that reflects a typical or frequent response n Mode: the number that appears most often n Median: the value whose occurrence lie in the middle of a set of numbers (half above and half below) n Mean: arithmetic average of a set of numbers

6. Measures of Central Tendency n Mean: arithmetic average of a set of numbers X=sample mean  Population mean

7. Measures of Variability n Reveal the typical differences between values in a data set n Frequency Distribution: tabulation of the number of times that each different value appears in a data set, shown as a percentage n Range: difference between the lowest and highest value in a data set

8. Measures of Variability n Standard Deviation: indicates the degree of variation or diversity in the values in such as way as to be translatable into a normal curve distribution n With a normal curve, the midpoint (apex) of the curve is also the mean and exactly 50% of the distribution lies on either side of the mean.

9. Midpoint (mean) 50% Normal, bell- shaped curve

10. Normal Curve and Standard Deviation

11. Other Descriptive Measures n Measures of skewness u Is the curve really bell-shaped or does it “skew” to one side or the other? u The closer the number given for skewness is to zero, the closer the distribution is to being bell-shaped. u A positive skewness means that the distribution has a tail to the right while a negative skewness means it has a tail to the left

12. Other Descriptive Measures n Kurtosis indicates how pointed or peaked the distribution. n A kurtosis value of zero or close to zero indicates that the distribution is bell-shaped.

13. When to use what

14. Microsoft Excel n Menu: Tools, Data Analysis, Descriptive Statistics n If Data Analysis is not present under Tools Bar then u go to Tools, Add-ins u check Analysis Toolpak and Analysis Toolpak VBA u click OK u Data analysis should appear under Tools now