Ncert -Class 7- maths -worksheet – Data Handling
Single choice correct answer
1. Rajan took six-math test and got scores of 78, 84, 92, 84, 68 and 96 (out of 100). Rajan’s mode score was
(a) 78.
(b) 84.
(c) 92.
(d) 96.
Ans: (b)
Explanation:
On arranging the test scores in ascending order, we get
68, 78, 84, 84, 92, 96
Since, the number 84 occurs the most at 2 times, hence, mode = 84
2.The temperature in degree Celsius over five days in June 2008 was 22, 18, 20, 22 and 23. The mean temperature was
(a) 23.
(b) 22.
(c) 21.
(d) 20.
Ans: (c)
3: The cost of five biscuits is Rs12, Rs20, Rs15, Rs18 and Rs24. The median cost is
(a) Rs12.
(b) Rs18.
(c) Rs20.
(d) Rs24.
Ans: (b)
Explanation:
On arranging the price in ascending order, we get
Rs12, Rs15, Rs18, Rs20, Rs24
Here, total number of observations = 5 (i.e., odd number) Median = Rs18 (The number in the middle)
4. The weekly salaries of six employees at McDonalds are Rs600, Rs680, Rs740, Rs680, Rs 720 and Rs800. The mean salary is
(a) Rs600.
(b) Rs680.
(c) Rs690.
(d) Rs700.
Ans: (d)
5.The ages in years of eight employees are 32, 41, 28, 54, 35, 26, 33 and 38. The range of the ages of the teachers is
(a) 26.
(b) 28.
(c) 31.
(d) 33.
Ans: (b)
Explanation:
Arranging the ages in ascending order, we get 26, 28, 32, 33, 35, 38, 41, 54
Range = largest value – smallest value = 54 – 26 = 28
6.The mean of first four prime number is
(a) 2.5.
(b) 4.25.
(c) 5.
(d) 17.
Ans: (b)
7.If the mean of five observations a, a+2, a+4, a+6 and a+8 is 11, then the mean of first three observations will be
(a) 7.
(b) 9.
(c) 10.
(d) 15.
Ans: (b)
8.Range of the given set of a data 11, 13, 17, 19, 23, 25, 29 is
(a) 11.
(b) 17.
(c) 18.
(d) 19.
Ans:(c)
Explanation:
Since,
The highest value in the given data = 29
And, the lowest value in the given data = 11
We know that, range = highest value – lowest value
Therefore, range = 29 – 11 = 18
9. For comparing two collections of data at a glance we use
(a) pie graph.
(b) bar graph.
(c) double bar graph.
(d) column graph.
Ans:(c)
Explanation:
Double bar graph helps to compare two collections of data at a glance.
10. The heights of 10 girls were measured in cm are 130, 128, 145, 129, 138, 147, 144, 152, 150 and 146. The range of the data is
(a) 24.
(b) 128.
(c) 152.
(d) 280.
Ans:(a)
Explanation:
On arranging the given data in ascending order, we get
128, 129, 130, 138, 144, 145, 146, 147, 150, 152.
Since, range = highest value – lowest value.
Thus, range = 152 – 128 = 24
11. The marks (out of 100) obtained by a group of students in an English test are 65, 64, 56, 79, 77, 54, 49, 80, 89 and What is the range of the marks obtained?
(a) 35 (b) 40
(c) 33 (d) 25
Ans (b) Range = highest marks – lowest marks = 89 – 49 = 40
12. The weights (in kg.) of 12 students of a class are: 35, 42, 35, 37, 45, 51, 32, 42, 32, 40, 45, and
51. How many modes in the given data?
(a) 2 (b) 3 (c) 4 (d) 1
(c) Arranging the given data in ascending order.
- 32, 32, 35, 35, 37, 40, 42, 42, 45, 45, 51 and 51. Here 32, 35, 42, 45 and 51 all occure two times.
- Hence, the given data has 5 modes.
13. There are six marbles in a box with with numbers from 1 to 6 marked on each of them. What is the probability of drawing a marble with number 3?
(a) 1/2 (b) 1/3
(c) 1/4 (d) 1/6
14. The scores in mathematics test (out of 25) of 15 students are as follow:
19, 16, 15, 24, 25, 23, 19, 20, 19, 6, 21, 22, 10, 19, 9, the median of the given the data is
15. Probability always lying between in ………….
16. When a die was thrown, then what will be the probability of getting 3?
Descriptive
Question
Determine the Mean of the first five whole numbers.
Solution
The first five Whole numbers present are 0, 1, 2, 3, and 4.
Mean is equal to = (Sum of first five whole numbers) divided by (Total Number of whole numbers)
Then,
The Sum of five whole numbers is = 0 + 1 + 2 + 3 +4
= 10
The total number of whole numbers present is = 5
Mean = (10/5)
= 2
Hence, the final Mean of the first five whole numbers is two.
Question
The marks out of 100 obtained by the group of students in the science test in their class are 85, 76, 90, 56, 95, 85, 39, 48, 81 and 75.
Now Find the:
(a) Highest and lowest marks obtained by the students.
(b) Range of the marks obtained.
(c) Mean marks obtained by the student’s group.
Answer
Firstly, we have to arrange the marks obtained by the group of students in the science test in an ascending order, which is
= 39, 48, 56, 85, 85, 90, 95, 75, 76, 81
(a) The highest mark obtained by the student on the test is= 95
The lowest mark obtained by the student on the test was = 39
(b) We know that range = Highest marks – Lowest marks
= 95 – 39
= 56
(c) Mean of Marks is equal to = Sum of all the marks obtained by these groups of students divided by the Total Number of students
= (39 + 48 + 56 + 85 + 85 + 75 + 76 + 81+ 90 + 95) divided by 10
= 730/10
= 73
Question
The heights of ten girls were measured in cm, and then the results are given as follows:
135, 150, 139, 146, 128, 151, 132,149, 143 and 141.
(a) What is the height found of the tallest girl?
(b) What is the height of the shortest girl?
(c) What is the range of the data?
(d) What is the mean height found of the girls?
(e) How many girls have heights that are more than the mean height?
Answer
Firstly we will have to arrange the given data in ascending order,
= 128, 141, 143, 132, 135, 139, 146, 149, 150 and 151
(a) The height of the tallest girl is 151 cm
(b) The height of the shortest girl is 128 cm
(c) Range of given data is equal to = Tallest height – Shortest height
= 151 – 128
= 23 cm
(d) Mean height of the girls is equal to = Sum of the height of all the girls divided by the total number of girls present
= (128 + 132 + 143 + 135 + 139 + 141 +146 + 149 + 150
+ 151) divided by 10
= 1414/10
= 141.4 cm
(e) Five girls have heights which is more than the mean height (which is 141.4 cm).
Question
The scores in a mathematics test (out of 25) of the 15 students in a class are as follows:
19, 25, 10, 5, 16, 25, 23, 20, 9, 20, 15, 20, 24, 12 and 20
Find the Mode and the Median of this data. Are they the same?
Answer
Arranging the following given scores in ascending order, we receive
5, 9, 10, 12, 15, 16, 19, 20, 20, 20, 20, 23, 24, 25 and 25
Mode,
Mode is determined as the value of the variable which is present most frequently.
Clearly, the number 20 occurs the maximum number of times.
Hence, the Mode of these given sores is 20
Median is,
The value of that middle observation is called the median of the data.
Here the n = 15, which is odd.
There, n is the number of students present.
∴median is the = value of ½ (n + 1)the observation.
= ½ (15 + 1)
= ½ (16)
= 16/2
= 8
Then, the value of the 8th term = 20
So, the Median is the 20.
Yes, both values are the same.
Question
The runs scored in the cricket match by the 11 players are as follows:
6, 15, 80, 120, 50, 100, 10, 15, 8, 10 and 15
Find the Mean, Mode and the Median of this data. Are these three same?
Answer
Arranging the runs scored in the cricket match by these 11 players in ascending order, we receive
6, 8, 10, 10, 15, 15, 15, 50, 80, 100 and 120
Mean,
The mean of the given above data is given as = Sum of all of the observations divided by the total number of observations in the above-given data.
= (6 + 8 + 10 + 10 + 15 + 15 + 15 + 50 + 80 + 100 + 120) divided by 11
= 429/11
= 39
Mode,
Mode is determined as the value of the variable which is present most frequently.
So, Clearly, the number 15 occurs the maximum number of times.
Hence, the Mode of these given scores is 15
Median is,
The value of the middle-most observation of the data.
Here n = 11, which is an odd number.
Where n is the number of players.
Hence median is = value of ½ (n + 1)the observation.
= ½ (11 + 1)
= ½ (12)
= 12/2
= 6
Then, the value of the 6th term = 15
Hence, the Median is 15.
No, these three (mean, Median and Mode) are not the same.