A

**90**%**confidence**level**means**that we would expect**90**% of the interval estimates to include the population parameter; a 95%**confidence**level**means**that 95% of the intervals would include the parameter; and so on.Then, what does the 95% confidence interval mean?

If repeated samples were taken and the

**95**%**confidence interval**was computed for each sample,**95**% of the**intervals**would contain the population**mean**. A**95**%**confidence interval**has a 0.95 probability of containing the population**mean**.**95**% of the population distribution is contained in the**confidence interval**.How do you find the level of confidence?

**To calculate a CI for the population mean (average), under these conditions, do the following:**

- Determine the confidence level and find the appropriate z*-value. Refer to the above table.
- Find the sample mean. for the sample size (n).
- Multiply z* times. and divide that by the square root of n.
- Take.