Oracle® Database SQL Language Reference 11g Release 2 (11.2) Part Number E1711803 


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Syntax
Purpose
STATS_BINOMIAL_TEST
is an exact probability test used for dichotomous variables, where only two possible values exist. It tests the difference between a sample proportion and a given proportion. The sample size in such tests is usually small.
This function takes four arguments: expr1
is the sample being examined. expr2
contains the values for which the proportion is expected to be, and p
is a proportion to test against. The fourth argument is a return value of type VARCHAR2
. If you omit the fourth argument, then the default is TWO_SIDED_PROB
. The meaning of the return values is shown in Table 53.
Table 53 STATS_BINOMIAL Return Values
Return Value  Meaning 


The probability that the given population proportion, 

The probability that the given population proportion, 

The probability that the given population proportion, 

The probability that the given population proportion, 
EXACT_PROB
gives the probability of getting exactly proportion p. In cases where you want to test whether the proportion found in the sample is significantly different from a 5050 split, p
would normally be 0.50. If you want to test only whether the proportion is different, then use the return value TWO_SIDED_PROB
. If your test is whether the proportion is more than the value of expr2
, then use the return value ONE_SIDED_PROB_OR_MORE
. If the test is to determine whether the proportion of expr2
is less, then use the return value ONE_SIDED_PROB_OR_LESS
.
STATS_BINOMIAL_TEST Example The following example determines the probability that reality exactly matches the number of men observed under the assumption that 69% of the population is composed of men:
SELECT AVG(DECODE(cust_gender, 'M', 1, 0)) real_proportion, STATS_BINOMIAL_TEST (cust_gender, 'M', 0.68, 'EXACT_PROB') exact, STATS_BINOMIAL_TEST (cust_gender, 'M', 0.68, 'ONE_SIDED_PROB_OR_LESS') prob_or_less FROM sh.customers;