Khan Academy: Sample Size for a Given Margin of Error for a Mean

Just how confident can we be with statistics calculated from a sample? Learners take this into account as they look at data from a sample of petroleum engineer salaries. They analyze the effect sample size has on a margin of error and...

Don't leave your classes vulnerable in their calculations! Help them understand the importance of calculating a margin of error to represent the variability in their sample mean. 

We know that sample data varies — it's time to quantify that variability! After calculating a sample mean, pupils calculate the margin of error. They repeat the process with a greater number of sample means and compare the results.

Error does not mean something went wrong! Learners complete a problem from beginning to end using concepts developed throughout the last five lessons. They begin with a set of data, determine a population proportion, analyze their result...

Use the power of mathematics to find the number of red chips in a bag — it's a little like magic! The activity asks learners to collect data to determine the percentage of red chips in a bag. They calculate the margin of error and...

Have you ever wondered about the proportion of ducks it would take to equal one bear's weight? (It's 423.) The video walks through how to solve for sample size when you already know the confidence, error, and proportion. It also graphs...

This set contains questions about statistics involving how to choose a sample size to fit a desired maximum error bound. The student learns to do this on confidence intervals for proportions as well as confidence intervals for means.

Video first briefly reviews the effect on the sampling distribution when the sample size increases then gives the formula for variance of the sample mean of the sampling distribution and formula for standard error of the mean.

Video reviews the central limit theorem and uses a simulation to illustrate sampling distributions and how they approach a normal distribution with larger sample sizes even if the original distribution was not normal.

Presents a problem that is similar to what might be on an AP Statistics exam. Walks students through each step for solving it and students input answers to questions along the way.