stDev() returns the standard deviation for the given value over a group. It uses a standard two-pass method, with N-1 as the denominator, and should be used when taking a sample of the population for an unbiased estimate. When the standard variation of the entire population is being calculated, stDevP should be used.
Syntax: stDev(expression)
Returns: A Float
Arguments
| Name | Description |
| expression | A numeric expression. |
Example
MATCH (n:Person)
RETURN stDev(n.age)
The standard deviation of the values in the property age for all nodes of the type ‘Person’ is returned.
Considerations
- All null values are excluded from the calculation.
stDev(null)returns 0.
Example
UNWIND [8, 9, 10, 11, 12, 15] AS val
RETURN stDev(val)
Returns the following Result
stDev(val) |
2.48327740429189 |