7.1 Quick revision

We recommend trying these Quick revision questions before your tutorial.
  1. A confidence interval is used to find an interval that probably (but not certainly) contains the sample value. True or false?
  2. All confidence interval are 95% confidence intervals. True or false?
  3. A standard error is calculated from population data, but a standard deviation is calculated from sample data. True or false?
  1. 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.
  2. 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).
  3. 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.