CONFIDENCE.T()

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

Definition. This function returns the confidence interval for the expected value of a random variable by using a Student’s t-test.

Arguments

• alpha (required). The probability of error used to calculate the confidence interval. The confidence interval equals 100*(1 – alpha)%, which means that an alpha of 0.05 indicates a 95-percent confidence level.

• standard_dev (required). The standard deviation of the population. The argument standard_dev is assumed to be known.

• size (required). The size of the sample.

Note

If one of the arguments isn’t a numeric value, the CONFIDENCE.T() function returns the #VALUE! error.

If alpha is less than or equal to 0 or greater than or equal to 1, the CONFIDENCE.T() function returns the #NUM! error.

If standard_dev is less than or equal to 0, the function returns the #NUM! error.

If size isn’t an integer, the decimal places are truncated. If size is equal to 1, the function returns the #DIV/0! error.

Background. See the background information for the CONFIDENCE.NORM() function.

Example. See the example for the CONFIDENCE.NORM() function.

See Also

CONFIDENCE(), CONFIDENCE.NORM(), T.TEST(), Z.TEST()

Sample Files

Use the CONFIDENCE.T worksheet in the Probability.xlsx sample file. The sample files are found in the Chapter12 folder. For more information about the sample files, see the section titled Using the Sample Files.