Graphical Presentation Of Data Using Pictogram, Pie Charts And Bar Charts

CONTENT:       i) The Pictogram

                        ii) The bar charts

                        iii) The pie charts

INTRODUCTION

A frequency table is a numerical presentation of data in an organized summary from.

Diagrams, symbols and pictures sometimes catch the eye more quickly than the number.

They also tell stories more easily than numbers. It is also observed that it is easier to understand frequency table than the raw data, another method of presenting data, which most graphical find easier than table, is observe method. Graphs help us to observe any patterns easily. Examples of these graphs are pictogram, bar chart, line graph and pie chart.

THE PICTOGRAM

This uses pictures to represent statistics information or data. The pictogram is also called an ideograph. A pictogram uses pictures or drawings to give a quick and easy meaning to statistical data. A pictogram is a simple way of representing data in which a number of indentical drawings or pictures and used to show the data. It is useful to use pictures which can easily be divided into halves, quarters and do on. A pictogram must have a key to show that each picture stands for. Also you need to give the diagram a title

Example: The following table shows the favorite sports of 75 students

Represent the data in the form of a pictogram.

Favourite sports                                 Frequency

Football                                               25

Wrestling                                            10

Boxing                                                 5

Table Tennis                                        15

Swimming                                           20

Evaluation Question

The following table shows the number of students in JSS 1 in different houses at a certain school.

Represent the data in the form of a pictogram

Reading Assignment

1. Essential mathematics for JSS 1 by AJS Oluwasanmi page 262-273
2. New general mathematics for JSS 1 by AJS Channon other. Page 145-151
3. MAN mathematics for JSS 1 page 211

THE BAR CHARTS

Bar chart is very like a pictogram. The bars have the same width and usually have equal spaces between them. Instead of using pictures as in case of the pictogram, we must use a bar to represent the frequency of each of the item. In drawing a bar chart, we must take the following features into consideration.

1. The charts consists of bars
2. The bars must be of equal width
3. The lengths of the bars are in proportion of the frequencies being represented. The bars may be vertical or horizontal

Example

The following figures show the number of children per family in a sample of 40 households

1, 2, 4, 3, 4, 3, 8, 3, 2, 2, 3, 2, 5, 6,

5, 4, 2, 1, 3, 2, 4, 5, 3, 8, 7, 6, 5,

4, 5, 7, 6, 3, 8, 6, 3, 5, 7, 5, 4, 3

• Prepare a frequency table for this data
• Draw a bar chart to illustrate the above data

Solution

• Frequency table

THEORY

1. 40 youths who were admitted into a mental hospital due to drug abuse were asked to name the types of drugs they often take. The table shows how they replied.

Indian hemp                            35%

Morphine                                 20%

Heroine                                    15%

Cocaine                                    30%

1. Represent this information in a pie chart

Find the number of youths in each category