Lesson: Grouped Frequency Tables: Estimating the Mean Mathematics

In this lesson, we will learn how to estimate the mean using grouped frequency tables.

Lesson Plan

Students will be able to

recognize that, for grouped data, you can only calculate an estimate for the mean if you do not know the source data,
calculate the midpoints of classes in a grouped frequency table,
form an extended frequency table to help calculate an estimate for the mean,
calculate an estimate for the mean of grouped data.

Q1:

The table shows students’ math test scores.

Work out an estimation for the mean of the scores.

Q2:

The following table represents the time taken by 35 people to travel to work.

Time (Minutes)	5–	10–	15–	20–
Frequency	10	15	7	3

Calculate an estimation for the mean number of minutes people take to travel to work. Round your answer to two decimal places.

Q3:

In an extract of a book, the number of words per sentence was counted. Find the missing numbers in the following table.

Use the previous table to calculate an estimate for the mean number of words. Give your answer to two decimal places.