comparison of estimators of standard deviation, mean moving range and median moving range to estimate process standard deviation using autocorrelated data

Mean Anisocoria ± Standard Deviation ( Range ) ( mm )

69 ABSTRACT PURPOSE: To report the incidence of anisocoria after unilateral excimer laser photorefractive kera-tectomy (PRK) for myopia and subsequent cortico-steroid therapy in a retrospective and prospective study and to explore possible etiologies. METHODS: The horizontal pupil diameter was determined in 6 patients (6 eyes) at 21.8 ± 12.6 months after unilateral wide-field excimer laser PRK ...

Estimating the sample mean and standard deviation from the sample size, median, range and/or interquartile range

BACKGROUND In systematic reviews and meta-analysis, researchers often pool the results of the sample mean and standard deviation from a set of similar clinical trials. A number of the trials, however, reported the study using the median, the minimum and maximum values, and/or the first and third quartiles. Hence, in order to combine results, one may have to estimate the sample mean and standard...

Trends in Stock Prices and Range to Standard Deviation Ratio

Hurst exponent (H) measured from R/S ratio, is being used as a measure to find predictability of a time series. The larger the H value, the stronger is the trending trait in the time series. In this paper, we estimated R/S ratio of several stock indexes of Indian market for 10 years. Though the overall Hurst exponent values for the selected series were close to 0.5, the value varied widely on p...

Construction of α-cut fuzzy X control charts based on standard deviation and range using fuzzy triangular numbers

Control charts are one of the most important tools in statistical process control that lead to improve quality processes and ensure required quality levels. In traditional control charts, all data should be exactly known, whereas there are many quality characteristics that cannot be expressed in numerical scale, such as characteristics for appearance, softness, and color. Fuzzy sets theory is a...

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

Standard deviation and standard error of the mean

In most clinical and experimental studies, the standard deviation (SD) and the estimated standard error of the mean (SEM) are used to present the characteristics of sample data and to explain statistical analysis results. However, some authors occasionally muddle the distinctive usage between the SD and SEM in medical literature. Because the process of calculating the SD and SEM includes differ...