Research studies that retest the same group of people throughout their lives are classified as studies.

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.

a. formula: f=ma or f/m=a

10,000n/1,267kg≈7.9m/

b. formula: a= and s=d/t

speed= 394.6/15

s=26.3m/s

a=

a=1.75m/

c. 7.9-1.75=difference of 6.15m/

d. the force that most likely caused this difference is friction forces

answer; i believe the correct answer is norming;

i would say b. research typically uses a variety of sources