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.