1 Statistical Analysis – Part 2 Yale Braunstein School of Information

2 Measures of Central Tendency  Distinguish between numerical & categorical data  Understand the differences between the different measures of “the average”  Mean  Median (middle value)  Mode (most common value) Example: David Lazarus on PG&E bonus payments, SF Gate, March 12, 2003.David Lazarus on PG&E bonus payments  Consider the dispersion around the center

3 Demos of Excel & SPSS  Sample data sets available from the Resources pageResources  Student height & weight  Oakland voter profile  U.S. colleges (with detailed comparison of 4 private colleges)  There are also links to:  Comparison of Excel & SPSS  MS for “Pivot Table Reports 101”“Pivot Table Reports 101”  SPSS “flow of logic” handouthandout  SPSS FAQ

4 Specific Topics Covered  Measures of central tendency (various forms of “averages”)  Frequencies  Histograms  Cross-tabulations  Value labels  Recoding & transforming data  Missing data or observations  Documenting data files, transformations, procedures, etc. [The last 5 are some of the strengths of SPSS]