Subject:- MATHEMATICS

Class:- JSS 1

References: – MF Macrae et al 2007. New General Mathematics for Junior Secondary Schools 1 pgs 140 – 151

J. S Oluwasanmi 2014. Essential Mathematics for Junior Secondary Schools 1 pgs 253 – 264

Week: 7

Topic:- Statistics 1: Purpose of data collection and Presentation of data

Subtopic: – Statistics, data and presentation

Content

Statistics is the branch of mathematics which deals with the study of data. Data mean information which are usually given in the form of numbers or facts. The information is called Statistical data or Statistics. Statistics involves:

Collecting data: to distinct ways of collection data are by carrying out experiments and by survey.

sorting and tabulating data

presenting data visually by means of diagrams

interpreting result

Types of Presentation

list and table

graphs

Lists and tables

Rank order: means in order from highest to lowest

Frequency table: means the number of times something happens.

Tally: tally chart are usually grouped in fives. Four tallies are drawn vertically with the fifth one drawn across them 1111

Graphical presentation

Pictogram: uses picture or drawing to give a quick and easy meaning to statistical data.

Bar chart: is very like pictogram. Data are represented by a bar instead of a picture. The height represent the frequency of each value.

Pie chart: A pie chart is a graph in the shape of a circular pie.

Examples

The following raw data shows the number of vehicle owned by 25 business men in Lagos. 2, 5, 3, 4, 6, 3, 4, 7, 5, 4, 7, 7, 8, 9, 5, 3, 4, 5, 7, 4, 4, 8, 2, 2, 5.

Arrange the data in increasing order

Arrange the data in decreasing order

How many men own 3 vehicles, 4 vehicles, 9 vehicles and less than 5 vehicles each?

Solution

Increasing order: 2, 2, 2, 3, 3, 3, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 7, 7, 7, 7, 8, 8, 9.

Creasing order: De9, 8, 8, 7, 7, 7, 7, 6, 5, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 3, 3, 3, 2, 2, 2.

3 men own 3 vehicles, 6 men own 4 vehicles, 1 man own 9 vehicles and 12 men own less than 5 vehicles each.

The following figures show the number of children per family in a sample of 40 households. 1, 2, 4, 3, 5, 3, 8, 3, 2, 2, 3, 4, 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.

Use a tally mark to prepare a frequency table for this data

What is the highest frequency of numbers of children per family?

Solution

Frequency table

No of children per familyTallyFrequency1ll22llll53llll llll94llll l65llll lll86llll47lll38lll3Total 40

9 households has 3 children each. The highest frequency of number of children per family is 3.

A student was given ₦600 in June as a pocket money. He spent the money as follows

Food = ₦200

Transport = ₦100

Books = ₦120

Rent = ₦150

Miscellaneous = ₦30

Draw a pie chart and bar chart to illustrate the data

Solution

There are 3600 in a full circle and the total amount spent was ₦600

₦1 represent by 3600

600 = 0.60 or multiply the fraction by 3600

ItemsAmount spent in ₦Angle

Method 1Angle

Method 2Food200200 x 0.6 = 1200200/600 x 3600 = 1200Transport100100 x 0.6 = 600100/600 x 3600 = 600Books120120 x 0.6 = 720120/600 x 3600 = 720Rent150150 x 0.6 = 900150/600 x 3600 = 900Miscellaneous3030 x 0.6 = 18030/600 x 3600 = 180 Total 60036003600

Assignment

Ex 18b question 1 and 3

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