Difference between revisions of "Documentation/How Tos/Calc: CHISQDIST function"
(New page: __NOTOC__ This function is not yet implemented but expected for OpenOffice.org version 3.1. == CHISQDIST == Calculates values for a χ<sup>2</sup>-distribution. === Syntax === <tt>''...) |
(→Semantic) |
||
| Line 23: | Line 23: | ||
:<math>= | :<math>= | ||
\begin{cases} | \begin{cases} | ||
| − | 0, & \textrm{if}\; x | + | 0, & \textrm{if}\; x \le 0 \\ |
| − | \displaystyle \frac {x^{\frac k 2 -1}\,\mathrm e^{- \frac x 2}} {2^{\frac k 2}\,\Gamma(\frac k 2) }, & \textrm{if}\; x | + | \displaystyle \frac {x^{\frac k 2 -1}\,\mathrm e^{- \frac x 2}} {2^{\frac k 2}\,\Gamma(\frac k 2) }, & \textrm{if}\; x > 0 |
\end{cases} | \end{cases} | ||
</math> | </math> | ||
| Line 32: | Line 32: | ||
:<math>= | :<math>= | ||
\begin{cases} | \begin{cases} | ||
| − | 0, & \textrm{if}\; x | + | 0, & \textrm{if}\; x \le 0 \\ |
| − | \displaystyle \int_0^x \frac {t^{\frac k 2 -1}\,\mathrm e^{- \frac t 2}} {2^{\frac k 2}\,\Gamma(\frac k 2) }\,\mathrm d t, & \textrm{if}\; x | + | \displaystyle \int_0^x \frac {t^{\frac k 2 -1}\,\mathrm e^{- \frac t 2}} {2^{\frac k 2}\,\Gamma(\frac k 2) }\,\mathrm d t, & \textrm{if}\; x > 0 |
\end{cases} | \end{cases} | ||
</math> | </math> | ||
Revision as of 21:55, 6 December 2008
This function is not yet implemented but expected for OpenOffice.org version 3.1.
CHISQDIST
Calculates values for a χ2-distribution.
Syntax
CHISQDIST(x; k; Cumulative)
- x is the number, at which you will evaluate the χ2-distribution.
- k sets the degrees of freedom for the χ2-distribution
- Constraint: k must be a positive integer
- Cumulative is a logical value.
- In the case Cumulative=TRUE() the cumulative distribution function is used, in the case Cumulative=FALSE() the probability density function. This parameter is optional. It is set to TRUE() if missing.
Semantic
CHISQDIST(x;k;FALSE()) returns values of the probability density function for the χ2-distribution:
CHISQDIST(x;k;TRUE()) returns the left tail probability for the χ2-distribution:
Example
CHSQDIST(2.7;3;FALSE())
- returns approximately 0.1699395239
CHSQDIST(2.7;3;TRUE())
- returns approximately 0.5597727056
Remarks
If you need CHISQDIST(x;k;TRUE()) with a non integer parameter k, then use GAMMADIST(x;k/2;2) instead.
In the density case the internal calculation uses logarithmic- and exponential function, if x >1425 or x · k > 1391000. The results are less accurate in those cases.
See also:
CHISQINV, LEGACY.CHIDIST, LEGACY.CHIINV, CHITEST
Functions listed alphabetically, Functions listed by category
Issues:
This function is not available in version 3.0 and earlier.
