Lesson Notes By Weeks and Term - Junior Secondary School 1







  • New General Mathematics, Junior Secondary School Book 1
  • Essential Mathematics for Junior Secondary School Book 1




CONTENT:    1. Definition

  1. Method of collecting data
  2. Classification of data




  • Statistics: is the branch of study of data. It involves (a) Gathering (i.e. collecting) data    (b) sorting and tabulating data      (c) presenting data visually by means of diagrams.
  • Data: (SINGULAR DATUM) means information which are usually given in the form of meaningful. Data may be categorized into quantitative and qualitative
  • Quantitative data: a numerical data, which is usually given in the form of a number or measurement is called quantitative data e.g. number of cars, height, number of towns etc. quantitative dateis either discrete or continuous.
  • Discrete data: are data which can be obtained by counting (not by measurement). Discrete data can only exact values such as whole numbers. E.g. 2 boys, 3 houses etc. hence discrete data have definite or exact values
  • Continuous Data: are data that can be obtained by measurement (not by counting). Continuous data can take any values within a given range. E.g. height 1.6cm, height 40.56cm etc.
  • Qualitative Date: this is a non-numerical value which is concerned with qualities such as names, places, color, taste, opinions, brightness etc. 




Explain briefly with an example (i) Discrete data    (ii) Continuous data



There are two discrete ways of collecting data. These are (a) by carrying out experiment (b) by survey 



  • By Carrying out Experiments: Data can be obtained from experimental work carried out in the laboratories by students or scientist for example, various measurements, such as temperature, pressure, weight and height of an object can be obtained by setting up an experiments.
  • By Survey: This collection of information or data on a subject. A survey may be carried out by using the existing published data, making observation and asking questions.


  1. Using existing published data: Existing data may be obtained from libraries, schools, newspaper, and government’s publications such as annual abstract of statistics, stake statistics, employment gazettes, books journals and other publications.
  2. Making Observation: This method involves collecting data by observation e.g. you can do a round traffic survey by counting and recording the various types of vehicles that ply a particular road.
  3. Asking questions: You can ask other people questions to obtain their views or vital information in two ways: i. by interviewing them ii. By giving those questionnaires to fill in their response.
  • By Interviewing: This involves asking other people questions in order to obtain vital information or strict pattern or information, in which the questions asked only general formal but the order or the way the questions are presented can vary. It must be noted that the interviewers must avoid bias, misleading ambiguous and offensive questions.
  • Questionnaires: This is the most popular method of collecting data. Questionnaires are list of questions designed to obtain or discover particular information in a survey. In questionnaires, everyone is asked the same questions. The questionnaires may be given directly to an individual or sent to them by post to fill in their response. The main advantage of postal questionnaires is that it can be sent to many people in another towns or cities. 



Mention two major ways that data can be collected. 


Reading Assignment

Essential mathematics for JSS 1 by AJS Oluwasanmi pages 253 – 255



Data can be obtained either by direct collection from respondents or form a data bank of a data collection agency. Data collected directly from information’s are called 

  1. Primary Data: are those from data banks are called secondary data.
  2. Secondary Data: these are obtained from data collection agencies, engaged in routine data collection for research and planning some of these agencies include:
  1. Federal Office of Statistics (FOS) Principal agency 
  2. Central Bank of Nigeria
  3. Statistics units of Ministries/Parastatals
  4. Commercial Companies/ Industries.



  1. Name two broad ways of classification of data
  2. Mention two agencies we can collect secondary data



Michael obtained the following scores in a Basic Technology examination:

65, 72, 58, 82, 74, 64, 78, 70, 80, 75, 68

Arrange these scores:

  1. In ascending order
  2. In descending order



Essential Mathematics for JSS 1 by AJS Oluwasanmi chapter 23 pages 255 – 260.

Exercise 23.2 No 1&2 page 258



  1. Which one of the following is a discrete data     A. 1.25     B. 425     C. 834      D. 5
  2. Data that is written in random order is called    A. qualitative data    B. raw data    C. quantitative data     D. discrete data     E. continuous data
  3. Which of the following must a questionnaires be?     A. simple     B. misleading     C. ambiguous     D. irrelevant      E. offensive
  4. We can represent data by _____________    A. line    B. dist    C. number     D. picture    E. double lines
  5. Statistics deals majorly on ___________     A. building     B. dancing    C. data    D. fish    E. animals 



  1. Mention 3 things you must avoid when designing a questionnaires
  2. In carrying out a survey, mention two ways, you can obtain information from people.

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