Difference between revisions of "Fisher's Exact Test"

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==='''Comparison of software===
 
==='''Comparison of software===

Revision as of 08:15, 19 August 2020

FISHERSEXACTTEST(DataRange,NewTableFlag)
  • is the array of x and y values.
  • is either TRUE or FALSE. TRUE for getting results in a new cube. FALSE will display results in the same cube.

DESCRIPTION

  • This function gives the test statistic of the Fisher's Exact Test.
  • Since this method is more computationally intense, it is best used for smaller samples.
  • Like the chi-square test for (2x2) tables, Fisher's exact test examines the relation between two dimensions of the table (classification into rows vs. columns).
  • For experiments with small numbers of participants (below 1,000), Fisher’s is more accurate than the chi-square test or G-test.
  • The null hypothesis is that these two classifications are not different.
  • The P values in this test are computed by considering all possible tables that could give the row and column totals observed.

ASSUMPTIONS

  • Unlike other statistical tests, there isn’t a formula for Fisher’s.
  • To get a result for this test, calculate the probability of getting the observed data using the null hypothesis that the proportions are the same for both sets.

EXAMPLE

SPREADSHEET
A B
1 5 3
2 8 9

=FISHERSEXACTTEST([A1:B2], true)

FISHER'S EXACT TEST
DATA-0 DATA-1 SUM
5 3 8
8 9 17
SUM 13 12 25
TABLE
COUNT PROBABILITY PROB
0 0.0011899313501144164 0.0011899313501144164
1 0.019038901601830662 0.019038901601830662
2 0.10471395881006865 0.10471395881006865
3 0.2617848970251716 0.2617848970251716
4 0.32723112128146453 0
5 0.2094279176201373 0.2094279176201373
6 0.06663615560640732 0.06663615560640732
7 0.009519450800915331 0.009519450800915331
8 0.0004576659038901602 0.0004576659038901602
SUMMARY
VARIABLE RESULT
ONE-TAIL 0.38672768878718533
TWO-TAIL 0.6727688787185354
EXACT HYPERGEOMETRIC PROB. 0.2617848970251716



Comparison of software

Conduct Fisher's exact test for the data in the range B2:C4.

Fish.JPG


SOLUTION
In z3:
Fishz.JPG

In R:
Fishr.JPG