The CONFIDENCE.T function returns the confidence interval for a population mean, using a Student's t distribution.

The Student's t-distribution (or simply the t-distribution) is useful when the sample size is particularly small. Interestingly, the history of the Student's t distribution has it's roots in the brewing of Guinness beer.

CONFIDENCE.T takes 3 required arguments and no optional arguments:

Syntax: CONFIDENCE.T(alpha, standard_dev, size)

#1)
Using the CONFIDENCE.T function:
#2)
The arguments for the CONFIDENCE.T function are:
Argument Required? Description
alpha Required The significance level used to compute the confidence level. The confidence level equals 100*(1 - alpha)%, or in other words, an alpha of 0.05 indicates a 95 percent confidence level.
standard_dev Required The population standard deviation for the data range and is assumed to be known.
size Required The sample size.
#3)
A few more things:
If any argument is nonnumeric, CONFIDENCE.T returns the #VALUE! error value.
If alpha ≤ 0 or alpha ≥ 1, CONFIDENCE.T returns the #NUM! error value.
If standard_dev ≤ 0, CONFIDENCE.T returns the #NUM! error value.
If size is not an integer, it is truncated.
If size = 1, CONFIDENCE.T returns the #DIV/0! error value.

Summary

The CONFIDENCE.T function returns the confidence interval for a population mean, using a Student's t distribution.
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