Difference between revisions of "Documentation/How Tos/Calc: PROB function"
From Apache OpenOffice Wiki
< Documentation | How Tos
m (→Example:) |
(added: evaluation as array formula) |
||
Line 9: | Line 9: | ||
: <tt>'''values'''</tt> is a range or array of numbers (possibly unordered). | : <tt>'''values'''</tt> is a range or array of numbers (possibly unordered). | ||
− | : <tt>'''probabilities'''</tt> is a range or array of numbers of the same size as <tt>'''values'''</tt>, indicating the corresponding probability (>0 and <=1) | + | : <tt>'''probabilities'''</tt> is a range or array of numbers of the same size as <tt>'''values'''</tt>, indicating the corresponding probability (>0 and <=1) that each value in <tt>'''values'''</tt> will occur. The numbers in <tt>'''probabilities'''</tt> must sum to 1 exactly. |
: <tt>'''PROB'''</tt> finds all <tt>'''values'''</tt> which are between <tt>'''start'''</tt> and <tt>'''end'''</tt> inclusive and returns the sum of their corresponding <tt>'''probabilities'''</tt>. | : <tt>'''PROB'''</tt> finds all <tt>'''values'''</tt> which are between <tt>'''start'''</tt> and <tt>'''end'''</tt> inclusive and returns the sum of their corresponding <tt>'''probabilities'''</tt>. | ||
: <tt>'''end'''</tt> may be omitted, in which case <tt>'''PROB'''</tt> returns the probability corresponding to <tt>'''start'''</tt> (or <tt>'''0'''</tt> if <tt>'''start'''</tt> is not present in <tt>'''values'''</tt>). | : <tt>'''end'''</tt> may be omitted, in which case <tt>'''PROB'''</tt> returns the probability corresponding to <tt>'''start'''</tt> (or <tt>'''0'''</tt> if <tt>'''start'''</tt> is not present in <tt>'''values'''</tt>). | ||
+ | |||
+ | |||
+ | : Advanced topic: <tt>'''PROB'''</tt> evaluates as an [[Documentation/How_Tos/Using_Arrays|array formula]] - see the examples. | ||
=== Example: === | === Example: === | ||
Line 24: | Line 27: | ||
<tt>'''PROB({3; 4; 5; 6}; {0.2; 0.4; 0.3; 0.1}; 4)'''</tt> | <tt>'''PROB({3; 4; 5; 6}; {0.2; 0.4; 0.3; 0.1}; 4)'''</tt> | ||
: returns <tt>'''0.4'''</tt>, the probability for <tt>'''4'''</tt>. | : returns <tt>'''0.4'''</tt>, the probability for <tt>'''4'''</tt>. | ||
+ | |||
+ | |||
+ | Evaluation as an [[Documentation/How_Tos/Using_Arrays|array formula]]: | ||
+ | |||
+ | <tt>'''PROB(A1:A2*2; B1:B2; 2)'''</tt> | ||
+ | : where cells A1, A2 contain 1, 4 and cells B1, B2 contain 0.3, 0.7, returns <tt>'''0.3'''</tt>. <tt>'''PROB'''</tt> forces evaluation as an array formula, so that <tt>'''A1:A2*2'''</tt> yields the array {2 | 8}. Thus <tt>'''PROB({2 | 8}; B1:B2; 2)'''</tt> is actually evaluated to give the result. | ||
+ | |||
+ | <tt>'''PROB(A1:A2; B1:B2/100; 4)'''</tt> | ||
+ | : where cells A1, A2 contain 1, 4 and cells B1, B2 contain 30, 70, returns <tt>'''0.7'''</tt>. <tt>'''PROB'''</tt> forces evaluation as an array formula, so that <tt>'''B1:B2/100'''</tt> yields the array {0.3 | 0.7}. Cells B1 and B2 effectively contain percentages here. | ||
=== See also: === | === See also: === | ||
[[Documentation/How_Tos/Calc: Statistical functions|'''Statistical functions''']] | [[Documentation/How_Tos/Calc: Statistical functions|'''Statistical functions''']] | ||
+ | |||
+ | [[Documentation/How_Tos/Using_Arrays|'''Using Arrays''']] |
Revision as of 19:21, 1 May 2008
PROB
Returns a result from a list of probabilities.
Syntax:
PROB(values; probabilities; start; end)
- values is a range or array of numbers (possibly unordered).
- probabilities is a range or array of numbers of the same size as values, indicating the corresponding probability (>0 and <=1) that each value in values will occur. The numbers in probabilities must sum to 1 exactly.
- PROB finds all values which are between start and end inclusive and returns the sum of their corresponding probabilities.
- end may be omitted, in which case PROB returns the probability corresponding to start (or 0 if start is not present in values).
- Advanced topic: PROB evaluates as an array formula - see the examples.
Example:
PROB({3; 4; 5; 6}; {0.2; 0.4; 0.3; 0.1}; 4; 6)
- returns 0.8, the sum of the probabilities for 4, 5 and 6.
PROB({2.2; 5; 1}; {0.5; 0.3; 0.2}; 0; 3)
- returns 0.7, the sum of the probabilities for 1 and 2.2.
PROB({3; 4; 5; 6}; {0.2; 0.4; 0.3; 0.1}; 4)
- returns 0.4, the probability for 4.
Evaluation as an array formula:
PROB(A1:A2*2; B1:B2; 2)
- where cells A1, A2 contain 1, 4 and cells B1, B2 contain 0.3, 0.7, returns 0.3. PROB forces evaluation as an array formula, so that A1:A2*2 yields the array {2 | 8}. Thus PROB({2 | 8}; B1:B2; 2) is actually evaluated to give the result.
PROB(A1:A2; B1:B2/100; 4)
- where cells A1, A2 contain 1, 4 and cells B1, B2 contain 30, 70, returns 0.7. PROB forces evaluation as an array formula, so that B1:B2/100 yields the array {0.3 | 0.7}. Cells B1 and B2 effectively contain percentages here.