TDIST function - The function returns the probability of the Student distribution in Excel

In probability statistics, calculating probability is a regular job and puts a lot of pressure on you. The following article introduces the TDIST function in detail to help you calculate the probability value of the Student distribution.

Description: The function returns the probability of the Student's t-distribution, the Student's t-distribution is applied in assuming a given hypothesis with a relatively small sample dataset.

Syntax: TDIST (x, degrees_freedom, tails) .

Inside:

- x: Value used to calculate the probability of distribution, is a required parameter.

- degrees_freedom: Number of degrees of freedom (in integer format), is a required parameter.

- tails: Determines the remainder of the return value, is a required parameter, and has the following values:

+ tails = 1 -> Function TDIST () returns the 1-sided distribution.

+ tails = 2 -> The TDIST () function returns the 2-sided distribution.

Attention:

- All parameters in the TDIST () function must be numeric or the #VALUE error function will be displayed .

- The value of x must be greater than zero otherwise the function returns the #NUM! Error value, in case you still want to get the probability of the value of x less than 0 note: TDIST (-x, df, 1) = 1 - TDIST (x, df, 1) .

- Where degrees_freedom The function returns the #NUM! Error value.

- If degrees_freedom and Tails are decimal numbers -> the function takes an integer part of these 2 parameters.

- The value of tails parameter is in file {1, 2} otherwise the #NUM!

- If tails = 1 -> TDIST = P (X> x) , if tails = 2 -> TDIST = P (| X |> x) = P (X> x) or = P (X

For example:

Calculate the probability of distributing 3.88 with the degrees of freedom 66 in the two cases of the tails parameter .

TDIST function - The function returns the probability of the Student distribution in Excel Picture 1

- TH1: Where tails = 1.

In the cell to calculate enter the formula: = TDIST (D6, D7, D8) .

TDIST function - The function returns the probability of the Student distribution in Excel Picture 2

Pressing the Enter key receives the result:

TDIST function - The function returns the probability of the Student distribution in Excel Picture 3

So the probability of 3.88 with a step count of 66 when tails = 1 has a value of 0.000121842.

- TH2: Where the parameter tails = 2.

Similar to case tails = 1 enter the formula = TDIST (D7, D8, D9) -> press Enter the result is:

TDIST function - The function returns the probability of the Student distribution in Excel Picture 4

- TH3: Suppose you want to calculate the probability of a value of -3.88 whose degrees of freedom is 66 in the case of tails = 1 .

If you enter the TDIST formula for a value of -3.88, the function returns an error value:

TDIST function - The function returns the probability of the Student distribution in Excel Picture 5

Because the SDIST function does not support when the parameter is less than 0. So to calculate the probability of -3.88, do the following: Calculate the probability of the value 3.88 -> probability of -3.88 = 1- SDIST (3.88) .

TDIST function - The function returns the probability of the Student distribution in Excel Picture 6

Above is the usage and special cases of TDIST function , hope to support you in the process of working.

Good luck!