Selma wants to know if seventh grade students prefer to do their math homework in silence or with background music. she polled the 27 students in her music class. nine students preferred to do their math homework in silence, and eighteen students preferred to do their math homework with background music.

yes, because she picked people in music class who enjoy music

Step-by-step explanation:

She only asked people in music class, so that would mean that if your in music class people would probably like music,  but people who were not  in music might not like hearing background music

what is a pre-existing condition claus?

means if you're already damaged some way when you take out a medical insurance you will not get full compensation for that injury that you already have.