Page 201 - Maths Skills - 7

Data Handling 199

5. Find the arithmetic mean of:

(i) first ten natural numbers
(ii) first eight odd numbers
(iii) first six prime numbers

6. Maitri throws a dice 7 times and obtained the following numbers:

6, 1, 3, 6, 2, 4, 5
Find the mean, the median and the mode.

7. The mean (x) of 17 observations is 92. What is the sum of all the observations?

8. Determine the mode of the following number of shirts sold by a shopkeeper on different days of a week:
16, 18, 20, 19, 20, 5, 20

Also, find the mean and the median.

9. The weights (in kg) of 16 students are given below.
60, 42, 53, 49, 40, 65, 73, 35, 38, 49, 47, 38, 42, 55, 50, 45

Find the median weight.

10. The mean of 16 items was found to be 30. Later, it was discovered that one value of 18 was wrongly
copied as 22. Find the correct mean.

BAR GRAPH
A bar graph is a pictorial representation of the numerical data by a number of bars or rectangles of equal width,
but varying heights.
Bar graph is also called a column graph. The bars are drawn Academic Years Number of Students
either horizontally or vertically with equal space between 2014–2015 50
them. The height (or length) of a bar depends upon the number 2015–2016 75
it represents. To understand this better, let’s take an example: 2016–2017 100
The numbers of students in Class VII in a school during 2017–2018 150
academic years 2014 – 2015 to 2018 – 2019 are given in the 2018–2019 175
following table.

The bar graph of the information given in the table can be
drawn by taking academic years on the horizontal line (X-axis)
and number of students on the vertical line (Y-axis). The graph
so obtained is called as vertical bar graph Fig. (a).

We can also represent the given data taking academic years
on Y-axis and number of students on X-axis. A graph of it
is shown Fig. (b), and is called as horizontal bar graph. It
should be noted that generally we prefer vertical bar graphs
rather than horizontal bar graphs.
Fig. (a)