Page 1 - WorkSheet-2 Ch.14 Statistics

SAI INTERNATIONAL RESIDENTIAL SCHOOL
Class: IX

Worksheet No.2 (Statistics)
Subject -Mathematics

Section A
Choose the correct option:

1 The mean of five numbers is 30. If one number is excluded, their mean becomes 1
28. The excluded number is
(a) 28 (b) 30 (c) 35 (d) 38

2 For drawing a frequency polygon of a continuous frequency distribution, we plot 1
the points whose ordinates are the frequencies of the respective classes and
abscissa are, respectively
(a) upper limits of the classes (b) lower limits of the classes
(c) class marks of the classes (d) upper limits of proceeding classes

3 Median of the following numbers4, 4, 5, 7, 6, 7, 7, 12, 3 is 1
(a) 4 (b) 5 (c) 6 (d) 7

Fill in the Blanks:
4 If the mean of the observations x, x + 3, x + 5, x + 7and x + 10 is 9, then mean of the 1
last three observations is ______

5 The mode of given data 15, 14, 19, 20, 14, 15, 16, 14, 15, 18, 14, 19, 15,17 and 15 is 1
___________

Answer the following
6 A child says that the median of 3, 14, 18, 20 and 5 is 18. What does not the child 1
understand about finding the median?

7 Consider the data : 2, 3, 9, 16, 9, 3, 9. Since 16 is the highest value 1
in the observations, is it correct to say that it is the mode of the data? Give
reason

Section B
8 Obtain the mean of the following distribution. 2

9 Ten observations 6, 14,15, 17, x + 1, 2x – 13, 30, 32, 34 and 43 are written in an 2
ascending order. The median of the data is 24. Find the value of x.

10 A class consists of 50 students out of which 30 are girls. The mean of marks 2