what is sd in statistics

In statistics, SD stands for standard deviation, which is a measure of how dispersed the data is in relation to the mean. It tells you how much the data deviates from the average or mean value. A low standard deviation indicates that the data is clustered tightly around the mean, while a high standard deviation indicates that the data is more spread out. Standard deviation is a useful measure of spread for normal distributions, where data is symmetrically distributed with no skew. It is widely used in experimental and industrial settings to test models against real-world data, and in finance, it is often used as a measure of the risk associated with price fluctuations of a given asset. To calculate the standard deviation, you need to subtract each data point from the mean, square the result, sum the squares, divide by the number of data points, and take the square root of the result.