Answer: blocking for gender
Explanation: Blocking refers to a experimental research procedure which involves splitting experimental variables into separate units. This speration is performed in other to avoid bias or effect this separately identified varibales may bring into our experiment if not tested separately. The blocks may be referred to as known categories upon which variables in an experiment may be divided such that treatment is applied to independently to the separate blocks or experimental unit. In the scenario above, the personnel director is blocking for gender by splitting the variables or participants based on gender.