TDIST

Formulas / TDIST
Compute the probability for the student t-distribution.

TDIST(x,deg_freedom,tails)

x - required, numeric value to evaluate the distribution on
degrees_freedom - required, integer
tails - required, 1 or 2, truncated to an integer

Examples

=TDIST(A2,A3,2)
The TDIST function is used to calculate the probability of obtaining a given value from the t-distribution. In the example above, it returns the two-tailed distribution of values in cell A2, cell A3, and column 2 of the worksheet. The two-tailed distribution is the probability of a given value occurring in either tail of the t-distribution.
=TDIST(A2,A3,1)
This example returns the one-tailed distribution of the difference between A2 and A3. The one-tailed distribution is the probability of a given value occurring in one tail of the t-distribution.
=TDIST(A2,A3,2, TRUE)
The TDIST function can also be used to calculate the probability of obtaining a given value in the t-distribution. This returns the probability of the difference between A2 and A3 occurring in the two-tailed t-distribution.
=TDIST(A2,A3,3,TRUE)
Finally, the TDIST function can be used to calculate the probability of obtaining a given value from the t-distribution. The example returns the three-tailed distribution of values in cell A2, cell A3, and column 3 of the worksheet. The three-tailed distribution is the probability of a given value occurring in any of the three tails of the t-distribution.

Summary

The TDIST function is used to calculate the probability of a student t-distribution in small sample data sets. It is available for backward compatibility and is improved by the T.DIST.2T and T.DIST.RT functions.

The TDIST function returns the probability for the student t-distribution, and is used for small sample data sets.
The new T.DIST.2T and T.DIST.RT functions provide improved accuracy.

Frequently Asked Questions

What are some important notes about using the TDIST function?

The degrees of freedom must be greater than or equal to 1.
The TDIST function assumes that the data is normally distributed.
The TDIST function returns a one-tailed probability by default. To get a two-tailed probability, set the tails argument to 2.

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