Amajor problem with using the polygraph as a lie detector is that

answer; the correct answer to the above statement is to increase the production of milk in a herd of milk cows, the highest producing cows were chosen as the mother;

answer:

d. because dr. laguardia selected a widely used measure, his study generalizes to has strong external validity. external validity has limited external validity. other applications of this measure.

the widely used measure that he applied to his experiment was the benton facial recognition test. it employed on to football players and as result, only players who suffered brain concussions did not pas this test. and although it has an external validity, it is limited because it isn't general to apply to other population.