Difference between revisions of "Documentation/How Tos/Calc: FTEST function"
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: <i>Advanced topic:</i> | : <i>Advanced topic:</i> | ||
| − | : The parameters <tt>'''data1'''</tt> and <tt>'''data2'''</tt> are always evaluated as [[Documentation/How_Tos/Using Arrays|array formulas]]. | + | : The parameters <tt>'''data1'''</tt> and <tt>'''data2'''</tt> are always evaluated as * [[Documentation/How_Tos/Using Arrays|array formulas]]. |
=== Example: === | === Example: === | ||
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: returns approximately <tt>'''0.82'''</tt>. The probability that the variances of these two samples are not significantly different is about 82%. Note: a real world example would need more data than this. | : returns approximately <tt>'''0.82'''</tt>. The probability that the variances of these two samples are not significantly different is about 82%. Note: a real world example would need more data than this. | ||
| − | + | {{Documentation/SeeAlso| | |
| − | [[Documentation/How_Tos/Calc: FDIST function| | + | * [[Documentation/How_Tos/Calc: FDIST function|FDIST]] |
| − | [[Documentation/How_Tos/Using Arrays| | + | * [[Documentation/How_Tos/Using Arrays|Array formulas]] |
| − | [[Documentation/How_Tos/Calc: Statistical functions| | + | * [[Documentation/How_Tos/Calc: Statistical functions|Statistical functions]] |
| − | [[Documentation/How_Tos/Calc: Functions listed alphabetically| | + | * [[Documentation/How_Tos/Calc: Functions listed alphabetically|Functions listed alphabetically]] |
| − | [[Documentation/How_Tos/Calc: Functions listed by category| | + | * [[Documentation/How_Tos/Calc: Functions listed by category|Functions listed by category]]}} |
=== Issues: === | === Issues: === | ||
* Earlier versions of Excel and the ODFF draft specification incorrectly claimed this was a one-tailed test. | * Earlier versions of Excel and the ODFF draft specification incorrectly claimed this was a one-tailed test. | ||
Revision as of 13:50, 25 February 2009
FTEST
Returns the result of an F-test.
Syntax:
FTEST(data1; data2)
- data1 and data2 are ranges or arrays (possibly of different size) containing numbers, on which the F-test is performed. The F-test calculates the likelihood that two samples have the same variance.
- In effect, the sample variances of data1 and data2 are calculated. data1 and data2 are re-ordered if necessary so that data1 has the larger variance (σ1) and data2 the smaller (σ2), and an F_value is calculated as σ1/σ2. The result returned by FTEST is 2*FDIST(F_value; COUNT(data1)-1; COUNT(data2)-1). This is the two-tailed probability that the variances in data1 and data2 are not significantly different. (The internal algorithms used by Calc are more sophisticated than this).
- Advanced topic:
- The parameters data1 and data2 are always evaluated as * array formulas.
Example:
FTEST({9;8;6;8}; {5;6;7})
- returns approximately 0.82. The probability that the variances of these two samples are not significantly different is about 82%. Note: a real world example would need more data than this.
Template:Documentation/SeeAlso
Issues:
- Earlier versions of Excel and the ODFF draft specification incorrectly claimed this was a one-tailed test.
