The CONFIDENCE.NORM function in Excel returns a value that represents the confidence interval for a population mean. The function takes as input the sample size and the standard deviation of the population. The function then returns a value that represents the confidence level for the population mean.
The syntax of CONFIDENCE.NORM in Excel is as follows:
=CONFIDENCE.NORM(confidence_level, standard_deviation, x_value, t_value)
where:
confidence_level is the required confidence level, expressed as a decimal value
standard_deviation is the standard deviation of the population, expressed as a decimal value
x_value is the observed value in the population
t_value is the t-value corresponding to the required confidence level and standard deviation
An example of how to use CONFIDENCE.NORM in Excel is to input a list of data points and then use the function to calculate a confidence interval for a population mean. The function takes into account the standard deviation of the data points and will return a 95% confidence interval. This can be helpful for determining if a population mean is statistically significant.
There are a few occasions when you should not use the CONFIDENCE.NORM function in Excel. One example is when you are trying to calculate the confidence interval for a population proportion, as this function is not designed to do so. Additionally, you should not use CONFIDENCE.NORM when your data is not normally distributed, as the function relies on this assumption.
There are a few similar formulae to CONFIDENCE.NORM in Excel. CONFIDENCE.T returns the confidence interval for a Student's t-distribution, while CONFIDENCE.CHISQ returns the confidence interval for a chi-squared distribution. CONFIDENCE.BINOM returns the confidence interval for a binomial distribution. Finally, CONFIDENCE.POISSON returns the confidence interval for a Poisson distribution.
