Buzz
This article introduces you to the CONFIDENCE.NORM function – one of the favored statistical functions in Excel.
Description: Obtain the confidence interval of the population through normalized distribution. Supported in Excel 2010 and later versions.
Syntax: CONFIDENCE.NORM(alpha, standard_dev, size)
In this context:
- alpha: Significance level for confidence calculation, with confidence level = 100*(1-alpha), is a mandatory parameter.
- standard_dev: Population standard deviation for the data range, considered as known, is a mandatory parameter.
- size: Sample size, is a mandatory parameter.
Note:
- If any parameter is not a numeric value -> the function returns an error value #VALUE!
- If alpha ≤ 0 or alpha ≥ 1 -> the function returns an error value #NUM!
- If standard_dev ≤ 0 -> the function returns an error value #NUM!
- If size is not an integer -> it is truncated to an integer.
- If size ≤ 1 -> the function returns an error value #NUM!
- If deg_freedom < 1 or deg_freedom > 10^10 -> the function returns an error value #NUM!
- Assuming alpha =0.5 -> the confidence interval is:
¯¯¯¯χ±1.96(σ√n)
Example:
Calculate the confidence interval for the population mean with the data in the table below:
- In the cell for calculation, enter the formula: =CONFIDENCE.NORM(D6,D7,D8)
- Press Enter -> the confidence interval for the population mean is:
- In case alpha ≤ 0 or alpha ≥ 1 -> the function returns an error value #NUM!
- In case size ≤ 1 -> the function returns an error value #NUM!
Here is a guide and some specific examples when using the CONFIDENCE.NORM function in Excel.
Wishing you all success!
