Search results
Results from the WOW.Com Content Network
The standard deviation (SD) is a single number that summarizes the variability in a dataset. It represents the typical distance between each data point and the mean. Smaller values indicate that the data points cluster closer to the mean—the values in the dataset are relatively consistent.
Basically, a small standard deviation means that the values in a statistical data set are close to the mean (or average) of the data set, and a large standard deviation means that the values in the data set are farther away from the mean.
What does standard deviation tell you? Standard deviation is a useful measure of spread for normal distributions. In normal distributions, data is symmetrically distributed with no skew. Most values cluster around a central region, with values tapering off as they go further away from the center.
Standard deviation tells us about the variability of values in a data set. It is a measure of dispersion, showing how spread out the data points are around the mean. Together with the mean, standard deviation can also indicate percentiles for a normally distributed population.
Standard deviation may be abbreviated SD or Std Dev, and is most commonly represented in mathematical texts and equations by the lowercase Greek letter σ (sigma), for the population standard deviation, or the Latin letter s, for the sample standard deviation.
Standard deviation measures the spread of a data distribution. The more spread out a data distribution is, the greater its standard deviation. For example, the blue distribution on bottom has a greater standard deviation (SD) than the green distribution on top:
Standard deviation tells you how spread out the data is. It is a measure of how far each observed value is from the mean. In any distribution, about 95% of values will be within 2 standard deviations of the mean.
What does the standard deviation tell us? The standard deviation describes or quantifies how widely values are typically scattered around the mean of a data set: This tells us how large a typical, representative deviation from the "average" is.
Standard deviation is a "spread data thermometer" that quantifies variability and guides sound analysis. While simple in principle, mastering its interpretation takes time. But the payoff is worth it – standard deviation can uncover patterns that averages alone miss.
Standard deviation is a statistic measuring the dispersion of a dataset relative to its mean. It is calculated as the square root of the variance. Learn how it's used.