## How do I calculate 95% confidence interval?

To compute the 95% confidence interval, start by computing the mean and standard error: M = (2 + 3 + 5 + 6 + 9)/5 = 5.

σM = = 1.118.

Z.95 can be found using the normal distribution calculator and specifying that the shaded area is 0.95 and indicating that you want the area to be between the cutoff points.

## What is the formula for confidence interval?

For a population with unknown mean and known standard deviation , a confidence interval for the population mean, based on a simple random sample (SRS) of size n, is + z* , where z* is the upper (1-C)/2 critical value for the standard normal distribution.

## What does a 95% confidence interval mean?

A 95% confidence interval is a range of values that you can be 95% certain contains the true mean of the population. This is not the same as a range that contains 95% of the values. But only a tiny fraction of the values in the large sample on the right lie within the confidence interval.

## What is a confidence interval in statistics?

In statistics, a confidence interval (CI) is a type of estimate computed from the statistics of the observed data. This proposes a range of plausible values for an unknown parameter (for example, the mean). The interval has an associated confidence level that the true parameter is in the proposed range.