Of the 40 students in Mr. Clayman's music class, 30 sing in the school choir. Express the part of the class that sings in the choir as
a fraction.
a. 2/5 b. 3/10 c. 30/100 d. 3/4

Aresearch study is done to find the average age of all u.s. factory workers. the researchers asked every factory worker in ohio what their birth year is. this research is an example of a census survey convenience sample simple random sample