## 7.1 Quick revision

We recommend trying these

*Quick revision*questions**before**your tutorial.- A
*confidence interval*is used to find an interval that probably (but not certainly) contains the*sample*value. True or false?

- All
*confidence interval*are 95% confidence intervals. True or false?

- A
*standard error*is calculated from population data, but a*standard deviation*is calculated from sample data. True or false?

**FALSE**. A CI is an interval which probably contains the**population**value. We already know the**sample**value... we don't need an interval for it.**FALSE**. Confidence intervals can be any percentage (though 90%, 95% and 99% CIs are the most common, and 95% easily the most common of all).**FALSE**. A*standard deviation*is a measure of variation in the*individuals*; a*standard error*is a measure of how much a sample summary value (such as the sample mean, or sample proportion) varies between samples.