● A confidence interval that estimates what proportion of a population has a certain characteristic. The confidence interval is not certain, just an inferred estimate. 90%, 95%, and 99% are common confidence levels.

● A z interval is a specific type of confidence interval which tells you a range where you can expect a particular mean or proportion to fall.

● The margin of error is a statistic expressing the amount of random sampling error in the results of a survey.

● A critical value is the value of the test statistic which defines the upper and lower bounds of a confidence interval, or which defines the threshold of statistical significance in a statistical test

● The standard error of a statistic is the standard deviation of its sampling distribution or an estimate of that standard deviation.