Annals of emergency medicine
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Descriptive statistics include measures of central tendency and variability. Measures of central tendency include mean, median, and mode. The mean is the arithmetic average of data from interval or ratio scales. ⋯ Interquartile range is data included between the 25th and 75th percentile of a distribution. Standard deviation describes variability of data about the sample mean, while standard error of the mean helps describe the distribution of several sample means about a true population mean. Finally, confidence intervals, which are derived from the standard error of the mean, define an interval likely to include a true population value, based on sample statistical values and probability charceristics of data distributions.