AP Statistics: Chapter 10 Practice Problems

1. The countries of Europe report that 46% of the labor force is female. The United Nations wonders if the percentage of females in the labor force is the same in the United States. Representatives from the United States Department of Labor plan to check a random sample of over 10,000 employment records on file to estimate a percentage of females in the United States labor force. They actually select a random sample of 525 employment records, and find that 229 of the people are females.

(a) Create the 90% confidence interval.

(b) Test a hypothesis to see if the percentage of females in the labor force in the United States differs from the one in Europe.

2. Cola makers test new recipes for loss of sweetness during storage. Trained tasters rate the sweetness before and after storage. From experience, the population distribution of sweetness losses will be close to Normal. Here are the sweetness losses (sweetness before storage minus sweetness after storage) found by tasters from a random sample of 10 batches of a new cola recipe:

(a)$Do$these$data$give$convincing$evidence$that$the$cola$lost$sweetness?$Carry$out$a$significance$test$$$$$$$$$to$help$answer$this$question$at$the$α=0.01$significance$level.$$$$$$$$$$$$$$$$$$$$(b)$Create$a$95%$confidence$interval.$$