Detecting outliers: Do not use standard deviation around the mean, use absolute deviation around the median

Detecting outliers: Do not use standard deviation around the mean, use absolute deviation around the median

MULTIPERIOD CREDIBILITIC MEAN SEMI-ABSOLUTE DEVIATION PORTFOLIO SELECTION

In this paper, we discuss a multiperiod portfolio selection problem with fuzzy returns. We present a new credibilitic multiperiod mean semi- absolute deviation portfolio selection with some real factors including transaction costs, borrowing constraints, entropy constraints, threshold constraints and risk control. In the proposed model, we quantify the investment return and risk associated with...

MEAN-ABSOLUTE DEVIATION PORTFOLIO SELECTION MODEL WITH FUZZY RETURNS

In this paper, we consider portfolio selection problem in which security returns are regarded as fuzzy variables rather than random variables. We first introduce a concept of absolute deviation for fuzzy variables and prove some useful properties, which imply that absolute deviation may be used to measure risk well. Then we propose two mean-absolute deviation models by defining risk as abs...

What to use to express the variability of data: Standard deviation or standard error of mean?

Statistics plays a vital role in biomedical research. It helps present data precisely and draws the meaningful conclusions. While presenting data, one should be aware of using adequate statistical measures. In biomedical journals, Standard Error of Mean (SEM) and Standard Deviation (SD) are used interchangeably to express the variability; though they measure different parameters. SEM quantifies...

Standard deviation, standard error. Which 'standard' should we use?

Standard deviation (SD) and standard error (SE) are quietly but extensively used in biomedical publications. These terms and notations are used as descriptive statistics (summarizing numerical data), and they are used as inferential statistics (estimating population parameters from samples). I review the use and misuse of SD and SE in several authoritative medical journals and make suggestions ...