Name: grubbs test for spotting data outliers
Uploaded: 2024-04-04T10:51:12.000Z
Duration: 1 min 2 s
Channel: JoVE

K12 Standards

Texas Essential Knowledge and Skills

High School

Chemistry

CHEM.2

CHEM.2.C

quantifying-and-rejecting-outliers-the-grubbs-test

Quantifying and Rejecting Outliers: The Grubbs Test

Тест Граббса, как и Q-критерий Диксона, является статистическим тестом для выявления выбросов в данных с нормальным распределением. Здесь количество наблюдений должно быть равно или превышать семь.
Для данного набора данных этот тест включает в себя вычисление статистики Граббса G, которая представляет собой отношение абсолютной разницы между сомнительным значением и средним значением к стандартному отклонению выборки.
Затем вычисленное значение G сравнивается с табличным критическим значением G для заданного уровня достоверности и количества наблюдений.
Если рассчитанное значение G превышает критическое значение G, сомнительное наблюдение рассматривается как выброс данных и отклоняется. 
В качестве альтернативы, если вычисленное значение G меньше критического значения G, данные сохраняют сомнительное наблюдение.

Количественная оценка и отклонение выбросов: Тест Граббса

Иногда набор данных может содержать записанное числовое наблюдение, которое сильно отличается от остальных данных. Предполагая, что данные распределены нормально, можно использовать статистический метод, называемый тестом Граббса, чтобы определить, действительно ли наблюдение является выбросом. Чтобы выполнить двусторонний тест Граббса, сначала вычислите абсолютную разницу между выбросом и средним значением. Затем рассчитайте соотношение этой разницы и стандартного отклонения выборки. Это число известно как статистика Граббса, 'G'. Когда рассчитанное значение G превышает критическое значение G для данного уровня достоверности и количества наблюдений, сомнительное наблюдение считается выбросом и удаляется из набора данных. Напротив, если рассчитанное значение G меньше критического значения G, сомнительное наблюдение не считается выбросом и, следовательно, сохраняется в наборе данных.

Тест Граббса, как и Q-критерий Диксона, является статистическим тестом для выявления выбросов в данных с нормальным распределением. Здесь количество ...

Education

JoVE Core

Analytical Chemistry

Аналитическая химия

Unit 1

Раздел 1

Chemical Applications of Statistical Analyses

Применение статистического анализа в химии

chemical-applications-of-statistical-analyses

KEY TERMS AND CONCEPTS

ОСНОВНЫЕ ТЕРМИНЫ И ПОНЯТИЯ

grubbs test for spotting data outliers

The Grubbs test is a statistical way to spot a possible outlier in a data set. It is used when the data is assumed to follow a normal distribution. A Grubbs test helps decide whether one unusual numerical value should be treated as a true outlier.

To run a two-tailed Grubbs test, first find the absolute difference between the questionable value and the mean. Then divide that difference by the sample standard deviation. The result is the Grubbs statistic, or G.

Next, compare the calculated G value with the G critical value for the chosen confidence level and the number of observations. If the calculated G is larger, the questionable value is considered an outlier and removed from the data set. If the calculated G is smaller, the value is not considered an outlier and is kept in the data set.

Grubbs Test for Spotting Data Outliers

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The Grubbs test is a statistical way to spot a possible outlier in a data set. It is used when the data is assumed to follow a normal distribution. A Grubbs test helps decide whether one unusual numerical value should be treated as a true outlier. To run a two-tailed Grubbs test, first find the absolute difference between the questionable value and the mean. Then divide that difference by the sample standard deviation. The result is the Grubbs statistic, or G. Next, compare the calculated G...

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key terms and concepts

Learn how the Grubbs test checks a normal data set for a possible outlier by comparing the G statistic with the critical value.

Grubbs Test for Spotting Data Outliers | JoVE K12

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Grubbs Test for Spotting Data Outliers

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