Difference between revisions of "Documentation/How Tos/Calc: CHISQDIST function"
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(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>''...) |
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__NOTOC__ | __NOTOC__ | ||
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== CHISQDIST == | == CHISQDIST == | ||
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:<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 31: | ||
:<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> | ||
=== Example === | === Example === | ||
| − | <tt>''' | + | {| |
| − | : returns approximately 0 | + | |- |
| + | |<tt>'''CHISQDIST(2.3;15;FALSE())'''</tt> | ||
| + | :returns approximately 0,000209862 | ||
| − | <tt>''' | + | <tt>'''CHISQDIST(2.3;2;FALSE())'''</tt> |
| − | : returns approximately 0. | + | :returns approximately 0,158318385 |
| + | |||
| + | |[[Image:ChiDistributionDensity.png|Graphs of Chi-distribution density functions]] | ||
| + | |} | ||
| + | |||
| + | {| | ||
| + | |- | ||
| + | |<tt>'''CHISQDIST(1.5;2;TRUE())'''</tt> | ||
| + | :returns approximately 0,5276334 | ||
| + | other valid call: <tt>'''CHISQDIST(1.5;2)'''</tt> | ||
| + | |[[Image:ChiDistributionCumulativeLeftTail.png|Chi-distribution cumulative functions]] | ||
| + | |} | ||
| + | |||
| + | {| | ||
| + | |- | ||
| + | |<tt>'''CHISQDIST(18;15;TRUE())'''</tt> | ||
| + | :returns approximately 0,73733444 | ||
| + | |[[Image:ChiDistributionLeftTailArea.png|Area under density function]] | ||
| + | |||
| + | [[Image:ChiDistributionCumulativeMarked.png|Chi-distribution with marked point]] | ||
| + | |} | ||
=== Remarks === | === Remarks === | ||
If you need <tt>CHISQDIST(x;k;TRUE())</tt> with a non integer parameter k, then use <tt>GAMMADIST(x;k/2;2)</tt> instead. | If you need <tt>CHISQDIST(x;k;TRUE())</tt> with a non integer parameter k, then use <tt>GAMMADIST(x;k/2;2)</tt> instead. | ||
| + | |||
| + | For to get the right tail for large values x, do not calculate 1 − CHISQDIST. It is less accurate in those cases than using CHIDIST. <tt>CHISQDIST(x;k;TRUE()) + CHIDIST(x;k) = 1</tt>. | ||
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. | 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. | ||
| − | === | + | === Issues === |
| − | + | This function is not available in version 3.0 and earlier. | |
| − | + | ||
| − | + | ||
| − | + | ||
| − | |||
| − | [[Documentation/How_Tos/Calc: | + | {{SeeAlso|EN| |
| − | [[Documentation/How_Tos/Calc: | + | * [[Documentation/How_Tos/Calc: CHISQINV function|CHISQINV]] |
| + | * [[Documentation/How_Tos/Calc: CHIDIST function|LEGACY.CHIDIST]] | ||
| + | * [[Documentation/How_Tos/Calc: CHIINV function|LEGACY.CHIINV]] | ||
| + | * [[Documentation/How_Tos/Calc: CHITEST function|CHITEST]] | ||
| − | + | * [[Documentation/How_Tos/Calc: Statistical functions|Statistical functions]] | |
| − | + | ||
| + | * [[Documentation/How_Tos/Calc: Functions listed alphabetically|Functions listed alphabetically]] | ||
| + | * [[Documentation/How_Tos/Calc: Functions listed by category|Functions listed by category]]}} | ||
| + | [[Category: Documentation/Reference/Calc/Statistical functions]] | ||
Latest revision as of 09:27, 17 July 2018
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
CHISQDIST(2.3;15;FALSE())
CHISQDIST(2.3;2;FALSE())
|
|
CHISQDIST(1.5;2;TRUE())
other valid call: CHISQDIST(1.5;2) |
|
CHISQDIST(18;15;TRUE())
|
|
Remarks
If you need CHISQDIST(x;k;TRUE()) with a non integer parameter k, then use GAMMADIST(x;k/2;2) instead.
For to get the right tail for large values x, do not calculate 1 − CHISQDIST. It is less accurate in those cases than using CHIDIST. CHISQDIST(x;k;TRUE()) + CHIDIST(x;k) = 1.
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.
Issues
This function is not available in version 3.0 and earlier.
See Also
