calibration spectrum was held out spectr.

[Natuli]

The calibration model was first built on a data set with a range of 1.34 – 2.82% w/w of
water. This model was later expanded using a data set with a range of 1.34 – 3.05% w/w
of water. The model was generated in a cross validation mode, namely at each cycle of
the cross validation, one quarter of the calibration spectra was held out at random and
used for verification of the resulting calibration model. The cycle continued until every
calibration spectrum was held out and used for validation.

Подскажите, пожалуйста, как правильно сказать "held out"
моя попытка: Модель была создана по типу перекресной проверки (кросс-валидации), а именно при каждом цикле валидации, одна четвертая часть спектра была составлена случайным образом и использовалась для верификации итоговой калибровочной модели. The cycle continued until every calibration spectrum was held out and used for validation.

[PicaPica]

one quarter of the calibration spectra was held out at random and
used for ... -- случайным образом выбранная четверть спектра использовалась для...

[Natuli]

Спасибо!