Page 200 - Maths Skills - 7

198 Maths

Let’s Attempt

Example 1: The runs scored by 10 players in a cricket match are: 26, 33, 47, 108, 0, 6, 73, 85, 54, 18. Find the
mean and the median.
Sum of all observations
Solution: Arithmetic mean = Number of observations

26 + 33 + 47 + 108 + 0 + 6 + 73 + 85 + 54 + 18 450
= = = 45
Here x = 45 10 10
To find the median, arrange the data in ascending order 0, 6, 18, 26, 33, 47, 54, 73, 85, 108
Q The number of observations n = 10

1 n  n   1 10  10   1

th
th
\ Median =  th + t  + 1 h value =  th + t  + 1 h = ( 5 + 6 value)




22  2   2 2  2   2
 

1 1
= (33 + 47) = × 80 = 40
2 2
Example 2: Find the median of the following data.
17, 43, 29, 10, 86, 111, 264.
Solution: Arranging the data in ascending order, we have 10, 17, 29, 43, 86, 111, 264
Here, n = 7, which is odd
+
 n +  1  71
\ Median =   th item =   th item = 4th item = 43
 2   2 
Example 3: Find the mode of the following data.
(i) 2, 3, 6, 6, 7, 10, 3, 6, 9, 11, 6 (ii) 25, 30, 24, 20, 13, 20, 30, 20, 20, 25, 24, 26, 30, 20
Solution: (i) In the given data, 6 occurs maximum number of times, i.e., 4 times. Hence, mode is 6.
(ii) Since, the value 20 occurs maximum number of times, i.e., 5 times. Hence, the mode is 20.

Exercise 1 2.1

1. The heights (in cm) of 11 students selected in the cricket team are:
140, 150, 139, 155, 127, 139, 142, 153, 139, 152, 145
Find the median.

2. The salaries of 15 employees in a company are:
7000, 6500, 3300, 5600, 2350, 2500, 8500, 1900, 10000, 7500, 3500, 4500, 5500, 3000, 9000

Find the mean of the data.
3. Sania scored the following marks in her exam.
49, 75, 60, 78, 70, 78

Find the mean, the median and the mode.
4. Find the median and the mode of the following sets of data.

(i) 1, 4, 6, 7, 9, 8, 2, 3, 6, 5, 6 (ii) 14, 15, 19, 23, 19