Standard deviation and Variance

A measure of the amount of variation or dispersion in a set of values.

That the data points tend to be close to the mean, indicating less variability.

That the data points are spread out over a wider range of values, indicating more variability.

The average of the squared differences from the mean, representing the degree of spread in a data set.

Standard deviation is the square root of variance.

Variance (σ²) = Σ (xi - μ)² / N, where xi is each value, μ is the mean, and N is the number of values.

In a normal distribution, approximately 68% of the data falls within one standard deviation of the mean, 95% within two, and 99.7% within three.

The middle value in a data set when the numbers are arranged in order.

The value that appears most frequently in a data set.

A graphical representation of data that shows the distribution through quartiles.