Which of the following situations could be used to produce an unbiased random sample?
a-Surveying students in a college psychology class to find out preferred majors of students at that school.
b-Asking people at the local supermarket what their favorite brand of ice cream is to find out what the preferred brand of ice cream is in that city.
c-Survey every tenth audience member leaving the American Country Music Awards and ask what their favorite type of music is.
d-Finding the heights of all 9th grade female students at a high school and using it to determine the average height of all girls at the school.
