Which of the Following Studies Would NOT Have a Possible

Multiple Choice

Which of the following studies would NOT have a possible threat of observer bias?

A) A study looking at the relationship between the frequency of eating fruits and vegetables and general physical fitness
B) A study looking at the relationship between college GPA and SAT scores
C) A study looking at the number of hours spent listening to music and singing ability
D) A study looking at the rate of text messaging in a day and writing/English composition skill
E) All of the above studies run the risk of observer bias