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.


  • 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.


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() ...

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