1. Sample Proportions
Section 9.2

2. p hat = X/n p hat = p p hat = [(p(1 – p)/n]
If the population is much larger than the sample, the count X will follow a binomial distribution
p hat = p
p hat = [(p(1 – p)/n]

3. p hat is an unbiased estimator of p
The standard deviation gets smaller as n increases

4. Rule of Thumb 1
Use the recipe for the standard deviation of p hat only when the population is at least 10 times as large as the sample

5. Rule of Thumb 2
Use the normal approximation to the sampling distribution of p hat for values of n and p that satisfy np  10 and n(1 – p)  10

6. Practice Problems
pg. 513 #