Daily DAX : Day 375 T.INV

T.INV Function in Power BI DAX

Description

The T.INV function in Power BI DAX returns the inverse of the Student's t-distribution (left-tailed) for a specified probability and degrees of freedom. It is used to calculate the critical value from the t-distribution, which is commonly applied in statistical analysis, such as hypothesis testing or confidence intervals.

Syntax

T.INV(Probability, Degrees_freedom)
  • Probability: A number between 0 and 1 representing the probability associated with the t-distribution.
  • Degrees_freedom: An integer indicating the number of degrees of freedom (must be positive).

Return Value

The function returns the t-value (critical value) of the left-tailed inverse of the Student's t-distribution.

Use Case

T.INV is used in scenarios involving statistical analysis, such as:

  • Calculating critical values for hypothesis testing (e.g., t-tests).
  • Determining confidence intervals for sample means.
  • Analyzing small sample sizes where the t-distribution is more appropriate than the normal distribution.

Example

Suppose you want to find the critical t-value for a 95% confidence level (probability = 0.95) with 10 degrees of freedom:

T.INV(0.95, 10)

Result: Approximately 1.812 (the t-value for a left-tailed test).

This value can be used to construct a confidence interval or perform a t-test in Power BI to analyze data, such as comparing sample means.

Notes

  • T.INV assumes a left-tailed distribution. For a right-tailed test, use -T.INV(1-Probability, Degrees_freedom).
  • Ensure Probability is between 0 and 1, and Degrees_freedom is a positive integer, or the function will return an error.

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