Video Transcript
We’ll now look at two further
questions in different scenarios.
Which of the following is a
representative sample? Is it (A) to find out how
students travel to school, student representatives from each grade ask a random
sample of 20 students from across the grade. (B) A hospital wants to
investigate the reasons why people go to the emergency room, so questionnaires
are handed out to a random sample of people waiting in the emergency room on a
Monday morning. (C) A market research company
wants to find out how much waste people recycle, so they survey 100 people at
the city recycling drop-off location. (D) A student wants to find out
how much students at their school enjoy math classes, so they give a
questionnaire to everyone at the math club.
A representative sample is a
subset of the population that seeks to accurately reflect the characteristics of
the larger group. This means that, where
possible, it needs to be unbiased, such that each member of the population has
an equal chance of being selected. In option (A), the population
is the students in the school. As they are selecting a random
sample of 20 students from each grade, this will represent the whole school. Option (A) is, therefore, a
representative sample of the whole school as students are not selected based on
gender, age, or interest.
In option (B), the population
is the people visiting the hospital’s emergency room. Whilst they are asking people
in the emergency room, they’re only asking on Monday mornings. This means that the sample is
not representative, as people visiting the emergency room at any other time
cannot be selected. In option (C), the market
research company wants to look at the whole population to see how much they
recycle. As they are only serving people
at the city recycling drop-off location, the survey is biased. The results would be skewed as
these people are more likely to recycle more waste than the general public. This means that option (C) is
not a representative sample.
In option (D), the population
is the students in the school. As they are only asking
students at math club, the questionnaire will be biased. Once again, this is not a
representative sample, as those students at math club are more likely to enjoy
math classes. Once again, this will skew the
results. The correct answer is option
(A).
