The table shows the results of a survey
that asked 20 students about their favourite breakfast. What is the probability that a randomly
selected student prefers eggs?
In this question, to calculate the
probability, we’re going to work out the experimental probability, which is also referred
to as relative frequency. We can use the calculation that the
relative frequency of an event E is equal to the number of times E occurs divided by the
total number of trials. So, for this question, to find the
probability that a student prefers eggs, this is equivalent to finding the relative
frequency of a student who prefers eggs and will be equal to the number of students who
prefer eggs over the total number of students.
We then use the table to establish that
there are 10 students who prefer eggs and 20 students in total. Even if we hadn’t been given that the
20 students were asked, we could’ve calculated this value by adding up the values of 10,
two, and eight in the table. We can then simplify our fraction 10
over 20 as one-half. So, our final answer as a decimal for
the probability that a randomly selected student prefers eggs is 0.5. In this case, our fractions 10 over 20,
one-half, and the decimal 0.5 would all be equally valid answers for the probability.