1. MA 102 Statistical Controversies Monday, April 15, 2002 Today: 95% confidence intervals - exercises General confidence intervals Reading: None new Exercises: 21.7, 21.18, 21.20, 21.22

2. Level C Confidence Interval for a Proportion Choose an SRS of size n from a large population containing an unknown proportion p of successes. Call the sample proportion of successes p^. Then an approximate level C confidence interval for the parameter p is p^  z*  (p^ (1 – p^) / n) where z* is the “critical value” for C.