{smcl} {* 23dar2002}{...} {hline} help for {hi:ksmapprox} {hline} {title:Smoothing including lowess} {p 8 12}{cmd:ksmapprox} {it:yvar} {it:xvar} [{cmd:if} {it:exp}] [{cmd:in} {it:range}] {bind:[{cmd:,} {cmdab:num:}{cmd:(}{it:#}{cmd:)} {cmdab:l:ine}} {cmdab:w:eight} {cmdab:low:ess} {cmdab:bw:idth}{cmd:(}{it:#}{cmd:)} {cmdab:lo:git} {cmdab:gen:erate}{cmd:(}{it:newvar}{cmd:)} {cmdab:nog:raph} {it:graph_options} ] {title:Description} {p}{cmd:ksmapprox} carries out unweighted and locally weighted smoothing of {it:yvar} on {it:xvar}, displays the graph, and optionally saves the smoothed variable. Among {cmd:ksmapprox}'s capabilities are lowess (robust locally weighted regression). {p}Note: {cmd:ksmapprox} differs from {cmd:ksm} in that it allows the option {cmd:num(#)} which specifies the number of points of {it:xvar} at which the smooth is computed. For lowess on a large number of observations (say, 10000), specifying, say, {cmd:num(100)} will mean that only 100 regressions are computed, rather than the 10000 that would have been computed using {cmd:ksm}. {title:Options} {p 0 4}{cmd:num}{cmd:(}{it:#}{cmd:)} specifies the number of observations for which the smooth will be computed. If {cmd:#}<=0 or is greater than the total number of observations, then the smooth is computed for all observations. Otherwise, the smooth is computed for the corresponding quantiles of {it:xvar}. For example, if {cmd:num(100)} is specified, the smooth is only computed for each percentile of {it:xvar}. For other values of {it:xvar}, a missing value is returned. {p 0 4}{cmd:line} specifies running-line least-squares smoothing; the default is running mean. {p 0 4}{cmd:weight} specifies use of Cleveland's (1979) tricube weighting function; the default is unweighted. {p 0 4}{cmd:lowess} is equivalent to specifying "{cmd:line weight}" and requests Cleveland's lowess running-line smoother. {p 0 4}{cmd:bwidth}{cmd:(}{it:#}{cmd:)} specifies the bandwidth. Centered subsets of {cmd:bwidth()}{cmd:*}N observations are used for calculating smoothed values for each point in the data except for end points, where smaller, uncentered subsets are used. The greater the {cmd:bwidth()}, the greater the smoothing. The default is 0.8. {p 0 4}{cmd:logit} transforms the smoothed {it:yvar} into logits. {p 0 4}{cmd:generate}{cmd:(}{it:newvar}{cmd:)} creates {it:newvar} containing the smoothed values of {it:yvar} in addition to or instead of displaying the graph. {p 0 4}{cmd:nograph} suppresses displaying the graph. {p 0 4}{it:graph_options} are any of the options allowed with {cmd:graph, twoway}; see help {help grtwoway}. {title:Examples} {p 8 12}{inp:. ksmapprox h1 depth, lowess}{p_end} {p 8 12}{inp:. ksmapprox h1 depth, lowess ylab xlab}{p_end} {p 8 12}{inp:. ksmapprox h1 depth, lowess ylab xlab bwidth(.4)} {title:Also see} Manual: {hi:[R] ksm} {p 0 19}On-line: help for {help ksm}, {help graph}, {help ipolate}, {help smooth}{p_end}