Alma wants to prove to her parents that listening to music while she studies for her tests will help her get better grades. She decides to ask 15 of her friends if they listen to music while they study for tests and what their grades are. She finds that her friends who have high grades also listen to music while they study for tests. She tells her parents that she has proven that listening to music while studying for tests will cause her grades to improve. What mistake has Alma made?

Question

anonymous · Answer

@arbershabani97

arbershabani97 · Answer

sorry I don't know the answer to this one

anonymous · Answer

She hasn't taken into consideration if her friends who have low grades also listen to music when they study. That would invalidate her conclusion.

Also, her sample space is small, being only taken from her friends. Maybe her friends are all smarter than average students.

anonymous · Answer

@mtbender74 these are the answer choices.

She did not separate her friends into different groups, and she didn't apply a treatment. 

 She did not separate her friends into different groups, and she used a survey to collect data. 

 She did not use a random sample, and she tried to show cause and effect with an experiment. 

 She did not use a random sample, and she tried to show cause and effect with an observational study.

anonymous · Answer

defintely not a random sample (my second point).

and it wasn't an experiment, it was an observational study.

the better thing for her to do would be to have a random group of people take two tests...one in which they listened to music while study and the other where they did not listen to music. Then she would see if the same person did better on the test with the music.

anonymous · Answer

Thankyou sm....this was correct (just took the test)