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LOGISTIC REGRESSION [VARIABLES =]dependent_varWITHpredictors[/CATEGORICAL =categorical_predictors] [{/NOCONST | /ORIGIN | /NOORIGIN }] [/PRINT = [SUMMARY] [DEFAULT] [CI(confidence)] [ALL]] [/CRITERIA = [BCON(min_delta)] [ITERATE(max_interations)] [LCON(min_likelihood_delta)] [EPS(min_epsilon)] [CUT(cut_point)]] [/MISSING = {INCLUDE|EXCLUDE}]

Bivariate Logistic Regression is used when you want to explain a dichotomous dependent variable in terms of one or more predictor variables.

The minimum command is

LOGISTIC REGRESSIONyWITHx1x2…xn.

Here, `y` is the dependent variable, which must be dichotomous and `x1` … `xn`
are the predictor variables whose coefficients the procedure estimates.

By default, a constant term is included in the model.
Hence, the full model is
*{\bf y}
= b_0 + b_1 {\bf x_1}
+ b_2 {\bf x_2}
+ \dots
+ b_n {\bf x_n}
*

Predictor variables which are categorical in nature should be listed on the `/CATEGORICAL`

subcommand.
Simple variables as well as interactions between variables may be listed here.

If you want a model without the constant term *b_0*, use the keyword `/ORIGIN`

.
`/NOCONST`

is a synonym for `/ORIGIN`

.

An iterative Newton-Raphson procedure is used to fit the model.
The `/CRITERIA`

subcommand is used to specify the stopping criteria of the procedure,
and other parameters.
The value of `cut_point` is used in the classification table. It is the
threshold above which predicted values are considered to be 1. Values
of `cut_point` must lie in the range [0,1].
During iterations, if any one of the stopping criteria are satisfied, the procedure is
considered complete.
The stopping criteria are:

- The number of iterations exceeds
`max_iterations`. The default value of`max_iterations`is 20. - The change in the all coefficient estimates are less than
`min_delta`. The default value of`min_delta`is 0.001. - The magnitude of change in the likelihood estimate is less than
`min_likelihood_delta`. The default value of`min_delta`is zero. This means that this criterion is disabled. - The differential of the estimated probability for all cases is less than
`min_epsilon`. In other words, the probabilities are close to zero or one. The default value of`min_epsilon`is 0.00000001.

The `PRINT`

subcommand controls the display of optional statistics.
Currently there is one such option, `CI`

, which indicates that the
confidence interval of the odds ratio should be displayed as well as its value.
`CI`

should be followed by an integer in parentheses, to indicate the
confidence level of the desired confidence interval.

The `MISSING`

subcommand determines the handling of missing
variables.
If `INCLUDE`

is set, then user-missing values are included in the
calculations, but system-missing values are not.
If `EXCLUDE`

is set, which is the default, user-missing
values are excluded as well as system-missing values.
This is the default.

Next: MEANS, Previous: GLM, Up: Statistics [Contents][Index]