Every fifth student who walked into the middle school was surveyed to determine his or her favorite subject. Out of 150 students
, 90 students stated that they like math class best. The staff concluded that about 60% of students like math class best. Is the sample method valid? Justify your answer. a)
The conclusion is invalid. This is a biased voluntary response sample.
b)
The conclusion is invalid. This is a biased convenience sample.
c)
The conclusion is valid. This is an unbiased systematic random sample.
d)
The conclusion is valid. This is an unbiased simple random sample.