The table of numbers shows the marks of 30 students in a mathematics exam. Using this data, complete the frequency table.
In this question, we are given the marks of 30 students and are asked to use this
data to complete the grouped frequency table. The first column corresponds to those students who achieved a mark of 20 to 23
inclusive. This means that we are looking for the numbers 20, 21, 22, or 23 in the table. The number 20 appears once, 21 appears twice, 22 does not appear, and 23 appears
twice. This means that the total frequency for the group 20 to 23 is five as five students
achieved a mark between 20 and 23 inclusive.
Next, we are looking for the students that achieved a mark of 24 to 27. There are eight such values, so the frequency in the second column is eight. The next group is for students who scored 28 to 31 marks. The frequency here is five, as one student scored 28 marks, one student scored 30
marks, and three students scored 31 marks. Next, we see that six students achieved a mark between 32 and 35 inclusive. Finally, we are looking for those students who achieved a mark of 36 of greater. From the table, we can see that there were six such students, so the final frequency
At this stage, it is worth checking that the five frequencies sum to 30, as the marks
of 30 students are shown in the table. Since five, eight, five, six, and six do sum to 30, we can conclude that these are
the correct frequencies for the number of students achieving each set of marks in
the grouped frequency table.