ladder.hlp

是一个经济学管理应用软件 很难找的 但是经济学学生又必须用到

{smcl}
{* 07mar2005}{...}
{cmd:help ladder}, {cmd:help gladder},{right:dialogs:  {bf:{dialog ladder}}  {bf:{dialog gladder}}}
{cmd:help qladder}{right:{bf:{dialog qladder}}{space 8}}
{hline}

{title:Title}

{p2colset 5 19 21 2}{...}
{p2col :{hi:[R] ladder} {hline 2}}Ladder of powers{p_end}
{p2colreset}{...}


{title:Syntax}

{phang}
Ladder of powers

{p 8 15 2}
{cmd:ladder} {varname} {ifin} [{cmd:,} {opth g:enerate(newvar)} {opt noa:djust}]

{phang}
Ladder-of-powers histograms

{p 8 16 2}
{cmd:gladder} {varname} {ifin} [{cmd:,}
 {it:{help ladder##histogram_options:histogram_options}}
 {it:{help ladder##combine_options:combine_options}}]

{phang}
Ladder-of-powers quantile-normal plots

{p 8 16 2}
{cmd:qladder} {varname} {ifin} [{cmd:,} 
{it:{help ladder##qnorm_options:qnorm_options}}
{it:{help ladder##combine_options:combine_options}}]

{p 4 6 2}
{cmd:by} may be used with {cmd:ladder}; see {helpb by}.


{title:Description}

{pstd}
{cmd:ladder} searches a subset of the ladder of powers for a transform that
converts {varname} into a normally distributed variable.  {helpb sktest}
tests for normality.  Also see {helpb boxcox}.

{pstd}
{cmd:gladder} displays nine histograms of transforms of {it:varname} according
to the ladder of powers.  {cmd:gladder} is useful pedagogically, but we do not
advise looking at histograms for research work; {cmd:ladder} or {helpb qnorm}
is preferred.

{pstd}
{cmd:qladder} displays the quantiles of transforms of {it:varname} according
to the ladder of powers against the quantiles of a normal distribution.


{title:Options for ladder}

{dlgtab:Main}

{phang}
{opth generate(newvar)} saves the transformed values corresponding to the
minimum chi-squared value from the table.  We do not recommend using 
{opt generate()} because it is quite literal in interpreting the 
minimum, thus ignoring nearly equal but perhaps more interpretable transforms.

{phang}
{opt noadjust} is the {opt noadjust} option to {helpb sktest}.


{title:Options for gladder}

{phang}
{marker histogram_options}
{it:histogram_options} affect the rendition of the histograms across all
relevant transformations.  See {helpb histogram}.  Here the {opt normal}
option is assumed, so you must supply the {opt nonormal} option to suppress
the overlaid normal density.  Also, {cmd:gladder} does not allow the
{opt width(#)} option of {cmd:histogram}.

{phang}
{marker combine_options}
{it:combine_options} are any of the options documented in 
{helpb graph combine}.  These include options for titling the graph (see 
{it:{help title_options}}) and options for saving the graph to disk (see 
{it:{help saving_option}}).


{title:Options for qladder}

{phang}
{marker qnorm_options}
{it:qnorm_options} affect the rendition of the quantile-normal plots across
all relevant transformations.  See {help diagnostic plots##options2:options2}
in diagnostic plots.

{phang}
{marker combine_options}
{it:combine_options} are any of the options documented in 
{helpb graph combine}.  These include options for titling the graph 
(see {it:{help title_options}}) and options for saving the graph to disk 
(see {it:{help saving_option}}).


{title:Examples}

{phang}{cmd:. ladder tempjuly}{p_end}

{phang}{cmd:. gladder mpg, fraction}{p_end}
{phang}{cmd:. gladder tempjuly, l1title("") ylabel(none) xlabel(none)}{p_end}

{phang}{cmd:. qladder tempjuly, ylabel(none) xlabel(none)}


{title:Also see}

{psee}
Manual:  {bf:[R] ladder}

{psee}
Online:  {helpb boxcox}, {help diagnostic plots}, {helpb lnskew0},
{helpb lv}, {helpb sktest}
{p_end}