The frequency table shows the marks a group of students received in an exam. How many students got 20 marks or more?
The 55 students in the class have been grouped according to the marks that they received. The top row in the table shows the grouped marks. And the bottom row shows the number of students who achieved a mark in that group.
For example, two students achieved a mark between 10 and 14. In order to work out how many students got 20 marks or more, we need to add together the frequencies for all of the groups in which the marks of 20 or more.
The divide between where students achieved less than 20 marks or 20 marks or more is here where I’ve put the green line.
There are four frequencies that we need to add together: the frequency for the group of students who achieve 20 to 24 marks, those who achieve 25 to 29, those who achieve 30 to 34, and those who achieved 35 to 39.
The sum of these four frequencies, 12 plus four plus nine plus seven, is 32. 32 students achieve 20 marks or more.