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help for ^lintrend^					(sg50: STB-30)
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Assessing linear trends
-----------------------

 ^lintrend^ yvar xvar [ ^if^ exp ] ^,^ { ^g^roups^(^#^)^ | ^r^ound^(^#^)^ | ^i^nteger }
        [ ^p^lot^(^{^mean^|^prop^|^log^|^both^}^)^  graph-options ]


^lintrend^ examines the linearity assumption for an ordinal or interval variable
against category means of a continuous outcome or log odds of a binary outcome.
^lintrend^ prints means or proportions and log odds.  Optionally a graph of the
means, proportions, or log odds can be displayed. 


Options
-------

{ ^g^roups^(^#^)^ | ^r^ound^(^#^)^ | ^i^nteger } chooses the method of grouping the
    xvar.  ^groups^ divides the xvar into # categories of similar sample size.
    ^round^ rounds xvar to the nearest #.  ^integer^ indicates an ordinal or
    nominal xvar; the original integer values for xvar are used.  One of these
    three alternatives must be specified.

^p^lot^(^{^mean^|^prop^|^log^|^both^}^)^ specifies which type of graph(s) to display.
    ^mean^ specifies a graph of means (for a continuous yvar).  ^prop^ specifies
    a graph of proportions (for a binary yvar).  ^log^ specifies a graph of the
    log odds (for a binary yvar).   ^both^ is the same as specifying both ^prop^
    and ^log^.  Only one alternative can be chosen.


Examples
--------

 . ^lintrend died age, groups(8) plot(prop) xlab ylab^

    Calculates the proportions and log odds of dying by age in 8 categories
    of similar sample size; plots graph of proportion of deaths by age category

 . ^lintrend died sbp, groups(12) plot(log) xlab ylab^

    Calculates the proportions and log odds of dying by systolic blood
    pressure in 12 categories of similar sample size; plots graph of log
    odds of deaths by sbp category, including "best fit" regression line    

 . ^lintrend chd chl, round(10) plot(both) xlab ylab^

    Calculates the proportion and log odds of developing coronary heart disease
    by cholesterol level in categories rounded to 10 unit increments of
    cholesterol; requests graphs for both proportions and log odds

 . ^lintrend chd ses3cat, integer^

    Calculates the proportion and log odds of developing coronary heart disease
    by each of 3 integer categories (1,2,3) of socioeconomic status; no graph

 . ^lintrend sbp age, groups(8) plot(mean) xlab ylab^

    Calculates mean systolic blood pressure for age in 8 categories of similar
    sample size; plots graph of mean systolic blood pressure by age category,
    including the "best fit" regression line    


Author
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        Joanne Garrett
        University of North Carolina
        FAX:  919-966-2274


Also see
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    STB:  STB-30:  sg50
 Manual:  [5s] logistic
On-line:  help for @logistic@