NCERT Solutions for Class 7 Maths
Chapter 3 Data Handling
Exercise 3.2
1. The scores in mathematics test (out of 25) of 15 students is as follows:
19, 25, 23, 20, 9, 20, 15, 10, 5, 16, 25, 20, 24, 12, 20
Find the mode and median of this data. Are they same?
Answer
Arranging the given data in ascending order,
5,9,10,12, 15, 16, 19, 20, 20, 20, 20, 23, 24, 25, 25
Mode is the observation occurred the highest number of times.
Therefore, Mode = 20
Median is the middle observation = 20
Yes, Mode and Median are same for given observation.
2. The runs scored in a cricket match by 11 players is as follows:
6, 15, 120, 50, 100, 80, 10, 15, 8, 10, 15
Find the mean, mode and median of this data. Are the three same?
Answer
Arranging the given data in ascending order,
6,8,10,10, 15, 15, 15,50, 80,100,120,
Mean = Sum of observations/Number of observations
= 6+15+120+50+100+80+10+15+8+10+15 / 11
= 429/11 = 39
Mode is the observation occurred the highest number of times = 15
Median is the middle observation = 15
Therefore, Mode and Median is 15.
No, the mean, median and mode are not same.
3. The weights (in kg.) of 15 students of a class are:
38, 42, 35, 37, 45, 50, 32, 43, 43, 40, 36, 38, 43, 38, 47
(i) Find the mode and median of this data.
(ii) Is there more than one mode?
Answer
Arranging the given data in ascending order,
32,35,36,37,38,38,38,40,42,43,43,43,45,47,50
(i) Mode is the observation occurred the highest number of times.
Therefore, Mode = 38 and 43
Median is the middle observation =40
(ii) Yes, there are 2 modes:
4. Find the mode and median of the data: 13, 16, 12, 14, 19, 12, 14, 13, 14
Answer
Arranging the given data in ascending order,
12,12,13,13, 14, 14, 14, 16, 19
Mode is the observation occurred the highest number of times = 14
Median is the middle observation = 14
5. Tell whether the statement is true or false:
(i) The mode is always one of the numbers in a data.
(ii) The mean is one of the numbers in a data.
(iii) The median is always one of the numbers in a data.
(iv) The data 6, 4, 3, 8, 9, 12, 13, 9 has mean 9.
Answer
(i) True, the mode is always one of the numbers in a data.
(ii) False, mean is not one of the numbers in a data because
Mean = Sum of observations / Number of observations
(iii) True, the median is always one of the numbers in a data
(iv) False,
Mean = Sum of all given observations/ number of observations
= (6 + 4 + 3 + 8 + 9 + 12 + 13 + 9)/8
= (64/8)
= 8
Hence, the given statement is false.