In mathematics:

**Σ**(uppercase) means summation (see sigma notation)**σ**(lowercase) means standard deviation**Σ**(uppercase) is the Greek numeral for 200

See all of sigma, there are 3 more in this node.

In mathematics:

**Σ**(uppercase) means summation (see sigma notation)**σ**(lowercase) means standard deviation**Σ**(uppercase) is the Greek numeral for 200