# DAV Class 7 Maths Chapter 12 Worksheet 3 Solutions

The DAV Maths Class 7 Solutions and DAV Class 7 Maths Chapter 12 Worksheet 3 Solutions of Data Handling offer comprehensive answers to textbook questions.

## DAV Class 7 Maths Ch 12 WS 3 Solutions

Question 1.
Find the mode of the following observations:
(z) 25, 14, 28, 17, 18, 14, 25, 14, 17, 14
(ii) 0, 6, 1, 5, 6, 2, 0, 4, 6, 3, 4, 6, 3, 1
(i) The given observations are
25, 14, 28, 17, 18, 14, 25, 14, 17, 14
Here the observation 14 repeats 4 times
∴ Modal observation = 14

(ii) The given observations are
0, 6,1, 5, 6, 2, 0, 4, 6, 3, 4, 6, 3,1
Here the observation 6 comes 4 times
∴ Modal observation is 6.

Question 2.
The following table shows the weight of 15 students. Find the mode.

 Weight (in kg) Number of students 46 3 51 1 53 5 56 2 60 4

The frequency of 53 kg is more i.e. 5
Mode is 53 kg. Question 3.
The following table shows sale of shirts having different sizes from a certain shop in a month. Find the mode. Number of shirts of size 39 is 31, which is maximum frequency.
Hence the Mode is 39.

Question 4.
In January 2015, the number of children in 10 families of a locality are:
4, 3, 4, 0, 2, 2, 5, 2, 1, 3 Find the mean, median and mode.
At the end of the year, two families having children 0 and 1 vacated the house. As a result, two more families having children 2 and 5 got the vacant accommodation. Find the new mean, median and mode.
The given observations are 4, 3, 4, 0, 2, 2, 5, 2, 1, 3
Mean = $$\frac{\text { Sum of the observations }}{\text { Number of observations }}$$
= $$\frac{4+3+4+0+2+2+5+2+1+3}{10}=\frac{26}{10}$$
= 2.6
Hence mean = 2.6
Arranging the observations in the increasing order,
0, 1, 2, 2, 2, 3, 3, 4, 4, 5
Number of observations = 10 (even)
Median = $$\frac{\frac{10^{\text {th }}}{2} \text { observation }+\left(\frac{10}{2}+1\right)^{\text {th }} \text { observation }}{2}$$
= $$\frac{5^{\text {th }} \text { observation }+6^{\text {th }} \text { observation }}{2}=\frac{2+3}{2}$$
= 2.5
Hence Median = 2.5

Mode: In the given observations 0,1, 2, 2, 2, 3, 3, 4, 4, 5
2 occurs 3 times the most. Therefore mode = 2
Now in the end of the year, the two observations 0 and 1 have been replaced by 2 and 5 respectively.
∴ New observations are 2, 5, 2, 2, 2, 3, 3,4, 4, 5
New Mean = $$\frac{2+5+2+2+2+3+3+4+4+5}{10}=\frac{32}{10}$$ = 3.2

New Median: Arranging the new observations in increasing order, 2, 2, 2, 2, 3, 3, 4, 4, 5, 5
Number of observation is 10(even)
New Median = $$\frac{\frac{10^{\text {th }}}{2} \text { observation }+\left(\frac{10}{2}+1\right)^{\text {th }} \text { observation }}{2}$$
= $$\frac{5^{\text {th }} \text { observation }+6^{\text {th }} \text { observation }}{2}=\frac{3+3}{2}$$ = 3
New Mode : Given observations are 2, 2, 2, 2, 3, 3, 4, 4, 5, 5
Here 2 repeats 4 times, the most
∴ Mode = 2.