INDIAN SCHOOL MUSCAT
DEPARTMENT OF MATHEMATICS
WORKSHEET ON STATISTICS
CLASS: IX
(2014-’15)
1. The mean of prime numbers between 20 and 30 is:
a) 24 b) 25 c) 26 d) 27
2. If the mode of 4, 9, 5, 4, 9, 5, 3, 9, 9 and x is 9 then the value of x is :
a) 4
b) 9 c) 5 d) any whole no.
3. The mean of x + 1, x + 3, x + 4, x + 8 is :
a) x + 1 b) x + 3 c) x + 4 d) x + 8
4. The following marks (out of 10) obtained by 20 students:
10, 4, 6, 5, 9, 3, 2, 10, 7, 6, 5, 4, 9, 10, 10, 3, 4, 10, 6, 9.
Construct a frequency table for the above data. Also find mean, median and
mode.
5. The following are the runs made by 22 players in a one day cricket series played
between India and Pakistan:
79, 28, 45, 99, 3, 46, 8, 0, 3, 7, 75, 24, 73, 122, 46, 27, 16, 7, 100, 3, 67, 53.
Construct a frequency distribution table for the above data with equal class
intervals, one of these being 0 – 20 (20 not included)
6. Find range of the data: 25, 18, 20, 22, 16, 6, 17, 12, 30, 32, 10, 19, 8 and 11.
7. The median of the following observations arranged in ascending order is 27.
Find x.
13, 15, 17, 21, x +2, x + 4, 32, 37, 41, 48.
8. Find the mean of the following distribution:
x
f
4
5
6
10
9
10
10
7
15
8
9. The class marks of a distribution are 37, 42, 47, 52 and 57. Determine the class
size and the class limits of the last class mark.
10.Find the value of p, if the mean of the following is 20.
x
f
5
6
10
p
15
6
20
10
25
5
11. The mean of 40 observations was 160. It was detected on rechecking that the
value 165 was wrongly copied as 125. Find the correct mean.
12.Find the mode of the observations 17, 23, 25, 18, 17, 23, 19, 23, 17, 26, 23. If 4
is subtracted from each observation, what will be the mode of the new
observation.
13.Determine the median of 24, 23, a, a – 1, 12 and 16, where a is the mean of 10,
20, 30, 40 and 50.
14.Construct a grouped frequency table for the following ages (in years) of 30
students using equal class intervals, one of them being 9 – 12 (12 not included)
18, 12, 7, 6, 11, 15, 21, 9, 15, 8, 13, 15, 17, 22, 19, 14, 21, 3, 8, 12, 17, 15, 6, 18,
23, 16, 9, 21, 11, 16.
Represent the above data by a histogram and frequency polygon on the same
Graph.
15. Draw a histogram for the following data.
Marks
Number of
candidates
10 – 15
7
15 – 20 20 – 25 25 – 30 30 – 40 40 – 60
9
8
5
12
12
60 – 80
8