**Concept:** Determining the Confidence Interval for a Population Proportion

**Concept:** Determining the Confidence Interval for a Population Proportion: Intro

**Problem:** From a sample of 1,000 women, ages 18+, it was found that 700 consider themselves a ?Belieber.?Find the margin of error that corresponds to a 95% confidence interval for the proportion of women who love Justin Bieber.

**Problem:** Referring to Practice 1, construct a 90% confidence interval for the proportion of women who do not enjoy Justin Bieber.

**Problem:** Apple conducted a survey to see what percent of people preferred the iPhone over all other types of smart phones. They found that 62% of the 100 sampled individuals preferred the iPhone. Construct a 99% confidence interval for the proportion of individuals who prefer the iPhone.

**Problem:** Referring to Practice 3, construct a 92% confidence interval for the proportion of individuals who prefer the iPhone over all other smartphones.

**Problem:** Referring to the results from Practice 3 and 4, why are these two confidence intervals different, even if they are based on the same sample information (the 100 people Apple surveyed).