The class marks of classes in a distribution are 6, 10, 14, 18, 22, 26, 30. Find

(a) class size (b) lower limit of second class
(c) upper limit of last class (d) third class

20 children were asked about the number of hours they watched to programmes in the previous week. The results were found as follows:

1 6 2 3 5 12 5 8 4 8
10 3 4 12 2 8 15 1 17 6

Make a grouped frequency distribution table for this data taking class width 5 and one of the class intervals as 5–10. How many children watched television for more than 10 hours a week? 

The marks obtained by 40 students of class IX in an examination are given below:

12, 8, 18, 8, 6, 16, 12, 5,

23, 2, 10, 20, 12, 9, 7, 6,

5, 3 , 5, 13, 21, 13,15, 20,

24, 1, 7, 16, 21, 13, 23, 18,

7, 3, 18, 17, 16, 16, 23, 12

Represent the data in the form of a frequency distribution using 15–20 (20 not included) as one of the class intervals.

24.

Prepare a freauency table from the data below:

Marks obtained	No. of students
More than or equal to 0	50
More than or equal to 20	48
More than or equal to 40	41
More than or equal to 60	30
More than or equal to 80	12

Three coins were tossed 30 times simultaneously. Each time, the number of heads occurring was noted drawn as follows:

0 1 2 2 1
2 3 1 1 0
13 1 1 2
2 0 12 1
3 0 0 1 1
2 3 2 2 0

Prepare a frequency distribution table for the data given above.

The blood groups of 30 students are recorded as follows:

A, B, O, A, AB, O,
A, O, B, A, O, B,
A, AB, B, A, AB, B,
A, A, O, A AB, B,
A, O, B, A, B, A

Prepare a frequency distribution table for the data. 

A survey conducted by an organisation for the cause of illness and death among the women between the ages 15—44 (in years) worldwide, found the following figures (in %):

(i) Represent the information given above graphically.
(ii) Which condition is the major cause of women–s ill health and death worldwide?
(iii) Try to find out, with the help of your teacher, any two factors which play a major role in the cause in (ii) above being the major cause.

The following data on the number of girls (to the nearest ten) per thousand boys in different sections of the Indian society is given below:

(i) Represent the information above by a bar graph.
(ii) In the classroom discuss what conclusion can be arrived at from the graph.

Given below are the seats won by different political parties in the polling outcome of a state assembly elections:

(i) Draw a bar graph to represent the polling results. [Hint: First make the class intervals continuous.]
(ii) Which political party won the maximum number of seats?

 The length of 40 leaves of a plant are measured correct to one millimetre, and the obtained data is represented in the following table:

(i) Draw a histogram to represent the given data.
(ii) Is there any other suitable graphical representation for the same data?
(iii) Is it correct to conclude that the maximum number of leaves are 153 mm long? Why?