AP Board 9th Class Maths Solutions Chapter 9 Statistics Ex 9.1

AP State Syllabus AP Board 9th Class Maths Solutions Chapter 9 Statistics Ex 9.1 Textbook Questions and Answers.

AP State Syllabus 9th Class Maths Solutions 9th Lesson Statistics Exercise 9.1

Question 1.
Write the mark wise frequencies in the following frequency distribution table.

Solution:

Question 2.
The blood groups of 36 students of IX class are recorded as follows.

Represent the data in the form of a frequency distribution table. Which is the most common and which is the rarest blood group among these groups ?

From the table, most common group is O and rarest group is AB.

Question 3.
Three coins were tossed 30 times simultaneously. Each time the occurring was noted down as follows :

Prepare a frequency distribution table for the data given above.
Solution:

Question 4.
A T.V. channel organized a SMS (Short Message Service) poll on prohibition on smoking giving options like A – complete prohibitions, B – prohibition in public places only, C – not necessary. SMS results in one hour were

Represent the above data as grouped frequency distribution table. How many appropriate answers were received ? What was the majority of people’s opinion ?
Solution:

Total appropriate answers received = 19 + 36 + 10 = 65
Majority of people’s opinion is prohibition in public places only i.e., B.

Question 5.
Represent the data in the given bar graph as frequency distribution table.

Solution:

Question 6.
Identify the scale used on the axes of the given graph. Write the frequency distribu- tion from it.
Solution:
Frequency distribution table :

Scale : X – axis : 1 cm = 1 class interval
Y – axis : 1 cm = 10 students

Question 7.
The marks of 30 students of a class, obtained in a test (out of 75), are given below : 42, 21, 50, 37, 42, 37, 38, 42, 49, 52, 38, 53, 57, 47, 29, 59, 61, 33, 17, 17, 39, 44, 42, 39, 14, 7, 27, 19, 54, 51. Form a frequency table with equal class intervals.
(Hint: One of them being 0 – 10)
Solution:

Question 8.
The electricity bill (in rupees) of 25 houses in a locality are given below. Construct a grouped frequency distribution table with a class size of 75.
170, 212, 252, 225, 310, 712, 412, 425, 322, 325, 192, 198, 230, 320, 412, 530, 602, 724, 370, 402, 317, 403, 405, 372, 413.
Solution:
The least value of observations = 170
The height value of observations = 724

Question 9.
A company manufactures car batteries of a particular type. The life (in years) of 40 batteries were recorded as follows.

Construct a grouped frequency distribution table with exclusive classes for this data, using class intervals of size 0.5 starting from the interval 2 – 2.5.
Solution: