. estat series educ, graph
warning: you have entered variable {\bftt{educ}} as continuous but it only has 18
        distinct values.  The estimates may differ substantially if you
        inadvertently include a discrete variable as continuous
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Computing approximating function
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Minimizing cross-validation criterion
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Iteration 0:  Cross-validation criterion =  1.30e+10
Iteration 1:  Cross-validation criterion =  1.30e+10
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Computing average derivatives
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Nonparametric series regression for IATE
Cubic B-spline estimation                  Number of obs      =          9,913
Criterion: cross-validation                Number of knots    =              3
\HLI{13}{\TOPT}\HLI{64}
             {\VBAR}               Robust
             {\VBAR}     Effect   std. err.      z    P>|z|     [95\% conf. interval]
\HLI{13}{\PLUS}\HLI{64}
        educ {\VBAR}   2532.489   1377.915     1.84   0.066    -168.1735    5233.152
\HLI{13}{\BOTT}\HLI{64}
Note: Effect estimates are averages of derivatives.
