Problem 1. Catherine Chao, Director of Marketing Research, is evaluating consumer acceptance of a new toothpaste package. She plans to use a 80% confidence interval estimate of the proportion of households which prefer the new packages; she will accept a 0.05 error. Previous studies indicate that new packaging has an approximately 70% acceptance rate. The sample size should be at least _______.
Problem 2. Financial analyst Larry Potts needs a sample of 100 securities listed on either the New York Stock Exchange (NYSE) or the American Stock Exchange (AMEX). According to the Wall Street Journal's "Stock Market Data Bank," 2,531 NYSE securities and AMEX 746 securities were traded on the previous business day. Larry directs his staff to randomly select 77 NYSE and 23 AMEX securities. His sample is a ____________.
- disproportionate systematic sample
- proportionate stratified sample
- disproportionate stratified sample
- proportionate systematic sample
Problem 3. Which types of data are normally used with parametric statistics?
- interval and ordinal
- ratio and ordinal
- nominal and ordinal
- interval and ratio