Estimating a Population Proportion

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 < p < 0.379

• 0.316 < p < 0.384

• 0.309 < p < 0.391

• 0.305 < p < 0.395

A survey of 800 women shoppers found that 17% of them shop on impulse. What is the 98% confidence interval for the true proportion of women shoppers who shop on impulse?

• 0.148 < p < 0.192

• 0.136 < p < 0.204

• 0.144 < p < 0.196

• 0.139 < p < 0.201

Answer explanation

The correct confidence interval is 0.139 < p < 0.201 because it captures the true proportion of women shoppers who shop on impulse with 98% confidence.

In a study of 500 people, 60% indicated they prefer online shopping. What is the 90% confidence interval for the true proportion of people preferring online shopping?

• 0.556 < p < 0.644

• 0.560 < p < 0.640

• 0.554 < p < 0.646

• 0.562 < p < 0.638

Answer explanation

The correct confidence interval is 0.556 < p < 0.644 as it captures the true proportion with 90% confidence.

A random sample of 100 WHS students found that 53 of them were in possession of a pencil. What is the p-hat for this sample?

• 0.53

• 0.5

• 0.47

• 1

Estimate the population proportion from the dotplot.

Mathematical Equivalence

ON

Suppose that a particular candidate for public office is, in fact, favored by 48% of all registered voters in the district. A polling organization takes a random sample of 500 voters, 245 of them favored the candidate.

What is p? ​ (a)  

What is p̂? ​ (b)  

• 48%

• 49%

• 500

• 50%

• 245

• 24.5%

• 0.48%

• 0.49%

Select the correct description

• Average Percent

• Population Proportion

• Sample Proportion

• Percent Slope of a Distribution

​ (a)   is a population proportion. ​ (b)   is a sample statistic.

• p

• p̂

An airline transports over 10,000 passengers daily, and the airline is curious what proportion of their passengers use mobile boarding passes instead of paper passes. They take a simple random sample of 80 passengers and find that 60 of them use mobile boarding passes. Based on this sample, which of the following is a 95% confidence interval for the proportion of passengers who use mobile boarding passes?

• (0.625, 0.875)

• (0.637, 0.863)

• (0.655, 0.845)

• (0.670, 0.830)

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, 0.780)

• (0.591, 0.812)

• (0.584, 0.830)

• (0.615, 0.805)