2 graph twoway qfit — Twoway quadratic prediction plots
Syntax
twoway qfit yvar xvar
if
in
weight
, options
options Description
range(# #) range over which predictions calculated
n(#) number of prediction points
atobs calculate predictions at xvar
estopts(regress options) options for regress
predopts(predict options) options for predict
cline options change look of predicted line
axis choice options associate plot with alternative axis
twoway options titles, legends, axes, added lines and text, by, regions, name,
aspect ratio, etc.
All options are rightmost; see [G-4] concept: repeated options.
yvar and xvar may contain time-series operators; see [U] 11.4.4 Time-series varlists.
aweights, fweights, and pweights are allowed. Weights, if specified, affect estimation but not how
the weighted results are plotted. See [U] 11.1.6 weight.
Options
range(# #) specifies the x range over which predictions are calculated. The default is range(. .),
meaning the minimum and maximum values of xvar. range(0 10) would make the range 0 to
10, range(. 10) would make the range the minimum to 10, and range(0 .) would make the
range 0 to the maximum.
n(#) specifies the number of points at which predictions over range() are to be calculated. The
default is n(100).
atobs is an alternative to n(). It specifies that the predictions be calculated at the xvar values. atobs
is the default if predopts() is specified and any statistic other than xb is requested.
estopts(regress options) specifies options to be passed along to regress to estimate the linear
regression from which the curve will be predicted; see [R] regress. If this option is specified,
commonly specified is estopts(nocons).
predopts(predict
options) specifies options to be passed along to predict to obtain the predictions
after estimation by regress; see [R] regress postestimation.
cline options specify how the prediction line is rendered; see [G-3] cline options.
axis choice options associate the plot with a particular y or x axis on the graph; see
[G-3] axis choice options.
twoway options are a set of common options supported by all twoway graphs. These options allow
you to title graphs, name graphs, control axes and legends, add lines and text, set aspect ratios,
create graphs over by() groups, and change some advanced settings. See [G-3] twoway options.