A school principal wants to determine which type of speaker the students prefer to invite to an assembly for the entire student population. Which survey method would produce the best representative sample?

A
survey every fifth person who shops at a mall
B
survey all of the students on the student council
C
survey every tenth student entering the school one morning
D
survey all of the students who went to the last basketball game

0:
Grace wants to estimate the percentage of students at her school who like yogurt. She will survey a random sample of 30students from the school’s population of 500 students.
Which of the following actions would best improve the validity of Grace’s estimate?

A
increase the sample size
B
increase the population
C
decrease the sample size
D
decrease the population

answeer both questions