How has the percentage of Americans reading newspapers, including in print and online, changed since 2006?
A. It has decreased from 37 percent to 17 percent.
B. It has decreased from 38 percent to 26 percent.
C. It has decreased from 43 percent to 37 percent,
D. It has increased from 9 percent to 17 percent.

all of them lol cause theres no map

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.