data analysis

Research Methods Knowledge Base is a very useful site

concepts and formulae

standard deviation for a sample from http://www.socialresearchmethods.net/kb/statdesc.php

standard deviation of a population from http://www.mathsrevision.net/gcse/pages.php?page=42

issues in survey research

• underrepresenting Democrats (N. Cohn, "Why Polls Tend to Undercoutn Democrats" NYY 30 Oct 14

on random digit dialing

• telephone exchanges in an area code (MA example)
• sample company which provides number generation
• HUD guide to random digit dialing