Question

A school has all of the students in grade 8 take a math test. Several sample are taken from the results. Which of the following samples is NOT likely to produce a representative sample of the population.
a. 35 students whose birthdays are in November
b. 40 students who did well on the math test
c. 45 students who have the same lunch period
d. 50 students whose first name start with M
(PLEASE EXPLAIN)

Answer 1

The answer is b. when taking a poll of a population one must use a completely unbiased control group. this means the have as little in common as possible. This means having a bunch of children good at maths be a control for a grade of carried maths scores is a terrible idea.