topic badge

9.04 Confidence intervals for sample proportions

Interactive practice questions

Given a sample size of $530$530 and a sample proportion of $40%$40%, find the approximate two-sided $95%$95% confidence interval for the population proportion using the given table.

Give your answer in the form $\left(a,b\right)$(a,b), and round your answer to two decimal places.

Easy
< 1min

To assist with road and transport planning, the council wants to estimate the proportion of people who use public transport to commute to work in the city.

They asked a sample of $500$500 people who work in the city if they use public transport to commute to work and $72.5%$72.5% of them responded that they did.

Easy
< 1min

Ten samples, each of size $150$150, have their two-sided $90%$90% confidence interval calculated. How many of these samples would we expect to contain the true population proportion?

Easy
< 1min

One hundred samples, each of size $300$300, have their two-sided $95%$95% confidence interval calculated. How many of these samples would we expect to contain the true population proportion?

Easy
< 1min
Sign up to access Practice Questions
Get full access to our content with a Mathspace account

Outcomes

ACMMM177

the concept of an interval estimate for a parameter associated with a random variable

ACMMM178

use the approximate confidence interval [ ˆp-√(ˆp(1−ˆp)/n, ˆp+z√(ˆp(1−ˆp)/n), as an interval estimate for p, where z is the appropriate quantile for the standard normal distribution

ACMMM179

define the approximate margin of error E=z√(ˆp (1−ˆp)/n and understand the trade-off between margin of error and level of confidence

ACMMM180

use simulation to illustrate variations in confidence intervals between samples and to show that most but not all confidence intervals contain p

What is Mathspace

About Mathspace