Term: 1^{st} Term
Week: 7
Class: Senior Secondary School 1
Age: 15 years
Duration: 40 minutes of 2 periods each
Date:
Subject: Economics
Topic: Data collection and presentation
SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to
INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source
INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures
INSTRUCTIONAL PROCEDURES
PERIOD 12
PRESENTATION 
TEACHER’S ACTIVITY 
STUDENT’S ACTIVITY 
STEP 1 INTRODUCTION 
The teacher reviews the previous lesson on the basic tools for economic analysis 
Students pay attention 
STEP 2 EXPLANATION 
She defines the various measures of central tendency

Students pay attention and participates 
STEP 3 DEMONSTRATION 
She performs calculations on each 
Students pay attention and participate 
STEP 4 NOTE TAKING 
The teacher writes a summarized note on the board 
The students copy the note in their books 
NOTE
MEASURES OF CENTRAL TENDENCY
Measures of central tendency means are values which show the degree to
which a given data or any given set of values will converge toward the
central point of the data. It is also called measure of location and is the
statistical information that gives the middle or centre or average of a set of
data. It includes mean, median and mode.
THE MEAN
Mean or arithmetic mean is defined as the sum of series of figures divided
by the number of observations. It is the commonest and the most widely
used among the other types of averages or measures of central tendency.
TYPES OF MEAN
Example
Calculate the arithmetic mean of the following scores of eight students in
an economics test. The scores are: 14, 18, 24, 16, 30, 12, 20, and 10.
Solution
Add up the scores
14+18+24+16+30+12+20+10 = 144
Number of observation (students) = 8
Arithmetic Mean =Sum of observations divided by Number of observations
= 144/8 =18
ADVANTAGES OF THE MEAN
DISADVANTAGES OF THE MEAN
THE MEDIAN
The median is an average which is the middle value when figures are
arranged in their order of magnitude either in ascending or descending
order, especially from ungrouped data.
ADVANTAGES OF THE MEDIAN
DISADVANTAGES OF THE MEDIAN
THE MODE
This is the most frequently recurring number in a set of numbers or data,
that is to say, it is the number or value with the highest frequency. It tells us
the observation which is most popular. The best and easiest way of
calculating the mode of any distribution is to form a frequency table for it.
ADVANTAGES OF MODE
DISADVANTAGES OF MODE
FORMULATION OF FREQUENCY TABLE FOR UNGROUPED DATA
UNGROUPED DATA:
Ungrouped data is one in which the raw data has occurrences or
frequencies more than and are without class intervals. In the formulation of
a frequency table for ungrouped data, two basic steps are taken.
PREPARATION OF A TALLY SHEET: This is when the variables are taken one after the other with a stroke called tally. The tally of five makes a bundle.
PREPARATION OF A FREQUENCY TABLE: The frequency table is simply obtained by adding the tallies together in a separate column referred to as frequency.
Example: The following are scores of thirty (30) students of SS 1 in an
economics test.
2, 4, 8, 8, 2, 6, 6, 8, 2, 4
8, 0, 8, 6, 0, 10, 2, 2, 0, 10
4, 6, 0, 10, 2, 2, 6, 6, 4, 2
SOLUTION
NUMBERS 
FREQUENCY 
TALLY 
0 
4 
//// 
2 
8 
//// /// 
4 
4 
//// 
6 
6 
//// / 
8 
5 
//// 
10 
3 
/// 
30
= 0 + 16 + 16 + 36 + 40 + 30
30
= 138
30
= 4.6
2
= 8
2
= 4
EVALUATION: 1. Define the following measures of central tendency
a. Mean
b. Median
c. Mode
a. Mean
b. Median
c. Mode
3. The following are scores of 20 students in an Economics test.
5 10 2 9 5 3 4
6 1 3 2 3 6 1
3 3 2 3 4 3
a. Prepare a frequency table with tally
Find the
b. Mean
c. Median
d. Mode
CLASSWORK: As in evaluation
CONCLUSION: The teacher commends the students positively