95% Confidence Interval for the population proportion
Describe a grouped frequency distribution; Percentile and rank
July 9, 2019Calculating probability of sample proportion
July 9, 2019The Friday after Thanksgiving is the biggest shopping day of the year. You are interested in the number of people who claim to have finished their Christmas shopping at the end of this weekend. On Monday, you take a random sampleof people by standing at a toll booth at 7:00 a.m. and asking every third commuter if he or she has finished Christmas shopping. Based on the last year’s data, you expect approximately 10% to claim completion of Christmas shopping. How many commuters must you sample of a 95% interval estimate to have a margin of error of +3%.
Solution. The margin of error ME=3%=0.03, phat=10%=010. For a 95% confidence level, …
In this solution, it consists of detailed steps of finding a 95% confidence interval for the population proportion.
