Bias and Variability Preview CT-STEM

Sample size and variability

Here's the same model, but now we're back to calculating means. Scroll down for instructions!

Questions

Please answer the questions below.

Question 4.1

Use your plan and investigate how changing the sample size affects the variability of the sampling distribution (you can show the standard deviation on your graphs in the same way that we showed the mean, go back to page 1 if you need to!). Was your prediction on the previous page correct?

Question 4.2

By what factor do you need to increase the sample size in order for the standard deviation to be cut in half?

Question 4.3

By what factor do you think you need to increase sample size in order to reduce the standard deviation to 1/3 of it's value?

Question 4.4

Based on you answers to the previous questions, make a guess about the formula for the standard deviation of a sampling distribution. In other words, what effect does sample size have on standard deviation and how does this show up in the formula? Use your knowledge from previous math courses to answer this question!

Question 4.5

When we're taking samples in real life in order to estimate the true value of a parameter, is it better to have more or less variation?

Notes

These notes will appear on every page in this lesson so feel free to put anything here you'd like to keep track of.