Video Transcript
Consider the given descending
cumulative frequency graph, which represents the age, in years, of people enrolled
in a certain online course. What is the total number of people
in the course?
We begin by recalling that the
descending cumulative frequency of a value 𝑥 indicates the frequency of values that
are greater than or equal to 𝑥. The starting value of any
descending cumulative frequency diagram is always equal to the total frequency. We can see from the graph that the
first coordinate is 20, 50. The 𝑥-coordinate tells us that
this point represents all the people enrolled on the course who are aged 20 or
greater. And the 𝑦-coordinate corresponds
to the corresponding descending cumulative frequency. It is this value of 50 at the first
point on our graph that corresponds to the total number of people.
We can therefore conclude that
there are 50 people enrolled on the online course.
