# degrees of freedom

The degrees of freedom is the minimum number of independent variables in a system whose values must
be specified in order to define the system. The number of degrees of freedom
equals the number of variables less the number of independent relations
between them (constraints). Thus Ohm's law provides one relation between three variables and there are two degrees
of freedom: if the resistance of wire and the current through it are specified,
both degrees of freedom have been used, and the voltage across the wire
is fixed. In statistics, for a sample of *n* members, the distribution
has (*n* – *m*) degrees of freedom where there are *m* constraints on the distribution.