Confidence Intervals of Proportions

In a survey of 2480 golfers, 15% said they were left-handed.  The survey's margin of error was 3%.  Construct a confidence interval for the proportion of left-handed golfers.

• (0.18 to 0.21)
• (0.12 to 0.18)
• (0.12 to 0.15)
• (0.11 to .19)

You take a poll and find that 34% of the 100 people you asked dislike school lunches.  Using a 95% confidence level, what is the margin of error?

• 0.093
• 0.047
• .034
• .34

400 randomly selected adults were sampled. The proportion of people who like ice cream was found to be 82%. Find the Margin of Error with 95% confidence for this study. 

• 0.074
• 0.192
• 0.037
• 0.368

The 99% confidence interval for a proportion is (0.54, 0.72). What is p̂?

• 0.63
• 0.18
• 0.09
• 0.66

A survey of 280 homeless persons showed that 63 were veterans.  Construct a 90% confidence interval for the proportion of homeless persons who are veterans.

• (0.161 to .289)
• (0.176 to 0.274)
• (0.184 to 0.266)
• (0.167 to 0.283)

Out of a group of 2584 voters, 1757 of them voted "yes" on a proposition. Construct a 95% confidence interval for the proportion of all voters who would vote "yes."

• [.662,.698]

• [.298,.342]

• [.302,.338]

• [.288,.352]

A sample of 400 racing cars showed that 80 cars cost over $700,000. What is the 99% confidence interval of the true proportion of cars costing over $700,000?

• (0.001, 0.005)

• (0.566, 0.693)

• (0.148, 0.252)

• (0.023, 0.045)

A recent study of 750 Internet users in Europe found that 35% of Internet users were women. What is the 95% confidence interval of the true proportion of women in Europe who use the Internet?

• (0.321, 0.379)

• (0.316, 0.384)

• (0.309, 0.391)

• (0.305, 0.395)

A survey of 800 women shoppers found that 17% of them shop on impulse. What is the 90% confidence interval for the true proportion of women shoppers who shop on impulse?

• (0.148, 0.192)

• (0.136, 0.204)

• (0.144, 0.196)

• (0.139, 0.201)

It was found that in a sample of 90 teenage boys, 70% of them have received speeding tickets. What is the 90% confidence interval of the true proportion of teenage boys who have received speeding tickets?

• (0.621, 0.779)

• (0.591, 0.812)

• (0.584, 0.830)

• (0.615, 0.805)