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SPSS® 12.0 Command Syntax Reference

SPSS® 12.0 Command Syntax Reference

SPSS® 12.0 Command Syntax Reference

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BINOMIAL Subcommand<br />

<strong>Syntax</strong><br />

NPAR TESTS 1085<br />

NPAR TESTS BINOMIAL [({.5})]=varlist[({value,value})]<br />

{p } {value }<br />

BINOMIAL tests whether the observed distribution of a dichotomous variable is the same as that<br />

expected from a specified binomial distribution. By default, each variable named is assumed<br />

to have only two values, and the distribution of each variable named is compared to a binomial<br />

distribution with p (the proportion of cases expected in the first category) equal to 0.5. The<br />

default output includes the number of valid cases in each group, the test proportion, and the<br />

two-tailed probability of the observed proportion.<br />

Operations<br />

Example<br />

• The minimum specification is a list of variables to be tested.<br />

• To change the default 0.5 test proportion, specify a value in parentheses immediately after<br />

keyword BINOMIAL.<br />

• A single value in parentheses following the variable list is used as a cutting point. Cases<br />

with values equal to or less than the cutting point form the first category; the remaining<br />

cases form the second.<br />

• If two values appear in parentheses after the variable list, cases with values equal to the<br />

first value form the first category, and cases with values equal to the second value form<br />

the second category.<br />

• If no values are specified, the variables must be dichotomous.<br />

• The proportion observed in the first category is compared to the test proportion. The<br />

probability of the observed proportion occurring given the test proportion and a binomial<br />

distribution is then computed. A test statistic is calculated for each variable specified.<br />

• If the test proportion is the default (0.5), a two-tailed probability is displayed. For any<br />

other test proportion, a one-tailed probability is displayed. The direction of the one-tailed<br />

test depends on the observed proportion in the first category. If the observed proportion<br />

is more than the test proportion, the significance of observing that many or more in the<br />

first category is reported. If the observed proportion is less than or equal to the test proportion,<br />

the significance of observing that many or fewer in the first category is reported. In<br />

other words, the test is always done in the observed direction.<br />

NPAR TESTS BINOMIAL(.667)=V1(0,1).<br />

• NPAR TESTS displays the Binomial Test table showing the number of cases, observed<br />

proportion, test proportion (0.667), and the one-tailed significance for each category.

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