A measure of dispersion, it reveals the degree to which individual data points in a set vary from the mean value. For example, a smaller number indicates data points are clustered closely around the average, suggesting less variability. Conversely, a larger number indicates data points are spread out over a wider range, implying greater variability.
Understanding the variability in a data set is fundamental across numerous disciplines. In scientific research, it is critical for assessing the reliability of experimental results. In finance, it quantifies the risk associated with investments. In manufacturing, it monitors the consistency of production processes. Recognizing data variability allows for more informed decision-making and robust analysis. Its roots lie in statistical theory developed during the 19th and 20th centuries, solidifying its place as a standard analytical tool.