diff --git a/src/libs/routes/dailyChargeAmount.js b/src/libs/routes/dailyChargeAmount.js
index 9a0bd00cc4df440de5e95a266652783eae14c98f..9640b706d6dd2a5d814d32f35c8feb0188f265a0 100644
--- a/src/libs/routes/dailyChargeAmount.js
+++ b/src/libs/routes/dailyChargeAmount.js
@@ -406,7 +406,7 @@ dailyChargeAmountApp.get('/average', rqf.parse(), rqf.build(), (req, res, next)
         .field('turma.etapas_mod_ensino_segmento_id', 'education_level_mod_id')
         .field('AVG(turma.duracao_turma)/60.0', 'average_class_duration')
         .field('MEDIAN(turma.duracao_turma)/60.0', 'median_class_duration')
-        .field('STDDEV_POP(turma.duracao_turma)/60.0', 'std_class_duration')
+        .field('STDDEV_SAMP(turma.duracao_turma)/60.0', 'std_class_duration')
         .field('QUANTILE(turma.duracao_turma, 0.25)/60.0', 'fstqt_class_duration')
         .field('QUANTILE(turma.duracao_turma, 0.75)/60.0', 'thdqt_class_duration')
         .group('turma.ano_censo')