Sample statistics, such as the sample mean or the sample proportion, can be used to estimate a population parameter (such as the population mean or the population proportion). For example, you can estimate the true mean weight of all newborn babies in the entire world by collecting a sample and using that sample to generate a 95% confidence interval.
Because the sample is a relatively little portion of the entire population, errors will have to be considered. Using a sample to create a range or interval of values that estimates a population value is called a “confidence interval.”
The formula for calculating a 95% confidence interval for a population mean is:
The general “Confidence Interval” formula is:
sample mean – E.