Statistical data preparation: management of missing values and outliers.
10.4097/kjae.2017.70.4.407
- Author:
Sang Kyu KWAK
1
;
Jong Hae KIM
Author Information
1. Department of Medical Statistics, School of Medicine, Catholic University of Daegu, Daegu, Korea.
- Publication Type:Review
- Keywords:
Bias;
Data collection;
Data interpretation;
Statistics
- MeSH:
Bias (Epidemiology);
Data Collection;
Statistics as Topic
- From:Korean Journal of Anesthesiology
2017;70(4):407-411
- CountryRepublic of Korea
- Language:English
-
Abstract:
Missing values and outliers are frequently encountered while collecting data. The presence of missing values reduces the data available to be analyzed, compromising the statistical power of the study, and eventually the reliability of its results. In addition, it causes a significant bias in the results and degrades the efficiency of the data. Outliers significantly affect the process of estimating statistics (e.g., the average and standard deviation of a sample), resulting in overestimated or underestimated values. Therefore, the results of data analysis are considerably dependent on the ways in which the missing values and outliers are processed. In this regard, this review discusses the types of missing values, ways of identifying outliers, and dealing with the two.
