TDIST

Office Components Spreadsheet Function

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TDIST

See Also

Returns the Percentage Points (probability) for the Student t-distribution where a numeric value (x) is a calculated value of t for which the Percentage Points are to be computed. The t-distribution is used in the hypothesis testing of small sample data sets. Use this function in place of a table of critical values for the t-distribution.

Syntax

TDIST(x,degrees_freedom,tails)

X   is the numeric value at which to evaluate the distribution.

Degrees_freedom   is an integer indicating the number of degrees of freedom.

Tails   specifies the number of distribution tails to return. If tails = 1, TDIST returns the one-tailed distribution. If tails = 2, TDIST returns the two-tailed distribution.

Remarks

  • If any argument is nonnumeric, TDIST returns the #VALUE! error value.
  • If degrees_freedom < 1, TDIST returns the #NUM! error value.
  • The degrees_freedom and tails arguments are truncated to integers.
  • If tails is any value other than 1 or 2, TDIST returns the #NUM! error value.
  • TDIST is calculated as TDIST = p( x<abs(X)), where X is a random variable that follows the t-distribution.

Example

The example may be easier to understand if you copy it to a blank spreadsheet.

How?

Data Description
1.96 Value at which to evaluate the distribution
60 Degrees of freedom
Formula Description (Result)
=TDIST(A2,A3,2) Two-tailed distribution (0.054644927 or 5.46 percent)
=TDIST(A2,A3,1) One-tailed distribution (0.027322463 or 2.73 percent)

Note   To view the number as a percent, select the cell and click Commands and Options on the toolbar. Click the Format tab, and then click Percent in the Number Format box.