Question

nus, time devoted by her for other subjects =
h
85-42
15
175 14x3
15 15
h
43
13
h. 2
15
h
15
EXERCISE 2.1
1. Solve:
9 4
3
3 2
0 2
(iv)
7
(ii) 4+
8
(m
)
5
11 15
5 7
+
8
(v
)
(vi)
8
7 2 3
+
(vii)
10 5 2
2.
Arrange the following in descending order:
2 2 8
1 3 7
9'3'21
5'7'10
In a "magic square", the sum of the numbers in each row, in each column and along
0 2+45687123078669​

Answer 1

Explanation:

Hello,

Solution:

1) Mean = sum of all observation/ Total number of observation

Total Students = 15

Value of observation= 41, 39, 48, 52, 46, 62, 54, 40, 96, 52, 98, 40, 42, 52, 60

Mean =

$\begin{gathered}\frac{41 + 39 + 48 +52 + 46 + 62 + 54 + 40 + 96 + 52 + 98 + 40 + 42 + 52 + 60}{15} \\ \\ = \frac{822}{15} \\ \\ = 54.8\end{gathered}$

Median:

1) Arrange data in ascending order

39,40,40,41,42,46,48,52,52,52,54,60,62,96,98

2) Total numbers of observation= 15

Odd: (n+1)/2

=(15+1)/2 = 8 th element is median

Median = 52

Mode:

1) Arrange data in ascending order

39,40,40,41,42,46,48,52,52,52,54,60,62,96,98

2) Count the frequency of each observation,the observation having most frequency is the mode

So, 52 appears 3 time,maximum time

Mode = 52

Hope it helps you.

Answer 2

Answer:

Solution:

To find the class mark (xi) for each interval, the following relation is used.

Class mark = + /

xi and fixi can be calculated as follows.

Number of plants number of houses xi fixi

0 – 2 1 1 1

2 – 4 2 3 2 x 3 = 6

4 – 6 1 5 1 x 5 = 5

6 – 8 5 7 5 x 7 = 35

8 – 10 6 9 6 x 9 = 54

10 – 12 2 11 2 x 11 = 22

12 – 14 3 13 3 x13 = 39

Total 20 162

From the table, it can be observed that

∑fi = 20

∑fixi = 162

Statistics- Exercise 14.1 – Class 10

= 162/20 = 8.1

Therefore, mean number of plants per house is 8.1.

Here, direct method has been used as the values of class marks (xi) and fi are small.