Standard Deviation?

Question

what is standard deviation a measure of? I've worked it out for some sets of data, and I think that it is a measure of spread, but I'm not exactly sure.

is around 20 high when im working with numbers around 500mm, and 15 when im working with numbers around 200mm (these are hand and head sizes)

Answer 1

Standard deviation is a measure of deviation from a reference value (mean) of certain values of a sample.

This is calculated as follows,

s = squreroot{ E(x^2) - E(x)^2}

where E(x) = expected value of "x"

Answer 2

1. The standard deviation is a statistic that tells you how tightly all the various examples are clustered around the mean in a set of data.

2. The standard deviation is one of several indices of variability that statisticians use to characterize the dispersion among the measures in a given population.

3. A measure of the dispersion of a set of data from its mean. The more spread apart the data is, the higher the deviation.

4. In finance, standard deviation is applied to the annual rate of return of an investment to measure the investment's volatility (risk).

I hope, now you know.

All the best.

Answer 3

yea ur right it measures spread...A large standard deviation indicates that the data points are far from the mean and a small standard deviation indicates that they are clustered closely around the mean.

Answer 4

In probability and statistics, the standard deviation of a probability distribution, random variable, or population or multiset of values is defined as the square root of the variance.

The standard deviation is the root mean square (RMS) deviation of the values from their arithmetic mean.

Answer 5

It's the measure of error I think