By studying this lesson, you will be able to,
● collect data using tally marks and
● represent data in tables and picture graphs.
With the intention of preparing a plan for a parking lot, Pradeepa and Dileepa were handed over to find the different types and corresponding numbers of vehicles that arrive on a normal day to a certain office.
Each time a vehicle arrived, to represent the type and the arrival, a segment of a line (/) is marked as shown in the tables, to the right of the type of vehicle. The symbol “/” is called a tally mark.
The leaflet prepared by Pradeepa is given below.
Complete the following table by counting the number of line segments there are to the right of each type of vehicle in the above leaflet.
The leaflet prepared by Dileepa is given below.
Find the number of vehicles of each type that arrived by counting the groups of 5 and remaining line segments in the above leaflet, and complete the following table.
Which of the two leaflets did you find it easier to use when you were completing the table?
It is easier and quicker to count the tally marks that have been separated into groups of five in Dileepa’s leaflet than to count the tally marks one by one in Pradeepa’s leaflet.
Accordingly, the leaflet prepared with the number of vehicles of each type that arrived at the office included in it, based on what Dileepa had noted down is given below.
Information that can be represented by numbers as above is considered as data.
Information such as the daily attendance of students in a school and the number of births recorded in a hospital are presented as data.
(1) The number of child births recorded during the first five months of the year in a certain hospital is given in the tally chart given below. Complete the table by writing down the number of child births that occurred during each month.
(2) The number of family members belonging to the families of the thirty six Grade 6 students in a certain class is given below.
Copy the following table and represent this data in it.
(3) The marks received for a test by thirty five students in a class is given below (The maximum marks that a student could receive for this test is 10).
(i) How many students received 10 marks?
(ii) Are there more students who received more than 8 marks or less
than or equal to 8 marks? Give reasons for your answer.
(4) The marks received by forty students for a science test is given below
(The maximum marks that a student could receive for this test is 15).
Represent this data in the following table using tally marks.
How many students received less than 10 marks ?
The different ways in which 35 grade 6 students of a certain school travel to school are given in the following table.
This data has been represented in another way below.
A representation of data such as the above is called as a picture graph. Number of data represented by a symbol in the picture graph should be indicated.
(1) The number of registered letters that a post office had to send out during the 5 week days of a certain week is given in the following table.
Denote 8 letters by a suitable symbol and represent this data in a picture graph.
(2) The number of customers that arrived at a certain bank during the working hours of a week day to carry out transactions is given in the following table.
(iii) Draw a picture graph to represent the number of customers who arrived at the bank to deposit money by using the above figure and if necessary, a half of it.
(3) A record of the arrival times of the employees of a certain office is given in the following table.
(a) Select a suitable symbol to represent this data in a picture graph.
(b) Write down the number of employees represented by
(i) the whole figure you selected.
(ii) half the figure you selected.
(iii) three quarters of the figure you selected.
(iv) a quarter of the figure you selected.
(3) Using this symbol, represent the above information in a picture
graph.