diff --git a/src/libs/routes/dailyChargeAmount.js b/src/libs/routes/dailyChargeAmount.js
index 3602ff3efccf161913156e28813b41f797fcc45b..54ef5beabc0aa84f611acb61e3a6412285838d79 100644
--- a/src/libs/routes/dailyChargeAmount.js
+++ b/src/libs/routes/dailyChargeAmount.js
@@ -406,7 +406,7 @@ dailyChargeAmountApp.get('/average', rqf.parse(), (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')