Subject : Mathematics
Form : Form 4 Dynamic
Number of Students : 21
Date : 3 December 2013 (Tuesday)
Time : 9.00am – 10.10am (70 minutes)
Topic : Statistics III
Subtopic : Mode and Mean of Grouped Data
Objectives : At the end of the lesson, students will be able to:-
(i) Determine the modal class from the frequency table of grouped data.
(ii) Calculate the midpoint of a class.
(iii) Calculate mean from the frequency table of grouped data.
Key Points :
What
Modal class
Class interval with the highest frequency
Midpoint of a class
Is the mean of the class interval.
½ (lower limit + upper limit)
Mean of grouped data
Frequency table
A table that lists the items and uses tally marks to record and show the number of times they occur.
How
Determine the modal class from the frequency table of grouped data
Step 1:
Determine if the class intervals are arranged in sequence: from the lowest class interval to highest class interval.
Step 2:
Circle the class interval with the highest frequency.
Calculate the midpoint of a class
Step 1: For each class interval, apply the formula below:
Midpoint of a class = ½ (lower limit + upper limit)
Calculate mean from the frequency table of grouped data
Step 1:
Determine if the class intervals are arranged in sequence in the 1st column, from lowest class interval to highest class interval.
Step 2:
Sum up the frequency in the 2nd column.
Step 3:
Find the midpoint of each class interval in the 3rd column by the formula:
Midpoint of a class = ½ (lower limit + upper limit)
Step 4:
Multiply midpoint with frequency and write in 4th column.
Step 5:
Mean of grouped data =
Why
Through the learning of statistics, students will be able to practice Bloom’s taxonomy skill of Analyzing.
Statistics is a good tool in all sectors to depict chunks of information in a friendly manner.
Students will be able to identify the sizes of a group of data