Aconfounding variable is an example of whereas an extraneous variable is an example of

A confounding variable is an example of systematic error, whereas an extraneous variable is an example of random error.
A confounding variable is a variable other than the independent variable that is found to vary systematically among the conditions. The systematic error varies among the conditions, so it is a confounding variable. The random error, on the other hand are something that the experimenter cannot control.