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E:\Working\Focus_Learning\Math_Genius-8\Open_Files\05_Chapter_4\Chapter_4
\ 06-Jan-2025 Bharat Arora Proof-6 Reader’s Sign _______________________ Date __________

Given below is the electricity consumption history for the last six months of Mr George’s house.

Consumption History

Billing Period Days Units Bill Current Subsidy Provisional Total Amount
Basis Demand Bill Refund Payable (in `)
01/07/24 to 02/08/24 33 954 Actual 8197.65 0.00 0.00 8200.00
30/05/24 to 30/06/24 32 1091 Actual 9738.80 0.00 0.00 9740.00

28/04/24 to 29/05/24 32 925 Actual 7947.85 0.00 0.00 7950.00
27/03/24 to 27/04/24 32 541 Actual 3826.60 0.00 0.00 3830.00

25/02/24 to 26/03/24 31 305 Actual 1668.00 –808.88 0.00 860.00
22/01/24 to 24/02/24 34 315 Actual 1785.20 –920.16 0.00 870.00
1. What is the range of current demand for the given data?

2. Find the average monthly payment of bills.

3. What is the median of the electricity consumption?
4. Can you find the mode of the days for which bills are generated?
5. The daily consumption of electricity in Mr George’s house is about 21 units. Is the daily
consumption in your house more or less than this one?

6. Draw a suitable graph to show the total amount payable per month.

Meaning of Data Handling

In real life, we get various information in the form of facts, numbers, tables, etc. from different
sources such as newspapers, magazines, TV, social media, etc. The information such as figures,
facts, numbers, etc. collected for a definite purpose is called data. In a broader sense, data handling
means collecting, organising, representing, analysing and interpreting data.
In this chapter, we shall learn more about organising data in the form of an ungrouped or a grouped
frequency distribution table and also a graphical representation of a grouped frequency table. We
shall also learn about one more pictorial representation of data known as a circle graph or pie chart.

Organising and Grouping Data

In previous classes, we have learnt to organise the data in a table using tally marks. Let us recall
it through an example. Let us consider the marks obtained by 30 students of Class VIIIA in a
mathematics periodic test.

15, 6, 12, 9, 10, 13, 14, 18, 17, 14, 20, 9, 12, 19, 18, 15, 11, 18, 8, 10, 15, 10, 13, 19, 12, 14, 15, 6, 15, 11

Here, the marks obtained by each student are called an observation. The data which are in an
unorganised form is called raw data or ungrouped data. The data in this form does not help to
draw any conclusions.

For example, the highest and the lowest marks cannot be found easily at a glance. It is very difficult
to interpret it. So, we organise the above data in a table, using tally marks.

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