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# Balbharati solutions for Class 9 chapter 7 - Statistics [Latest edition]

## Chapter 7: Statistics

Practice set 7.1Practice set 7.2Practice set 7.3Practice set 7.4Practice set 7.5Problem Set 7

#### Balbharati solutions for Class 9 Chapter 7 Exercise Practice set 7.1 [Page 111]

Practice set 7.1 | Q 1 | Page 111

The following table shows the number of Buses and Trucks in nearest lakh units. Draw percentage bar-diagram. (Approximate the percentages to the nearest integer)

 Year No. of Trucks No. of Buses 2005-2006 47 9 2007-2008 56 13 2008-2009 60 16 2009-2010 63 18
Practice set 7.1 | Q 2 | Page 111

In the table given below, the information is given about roads. Using this draw sub-divided and percentage bardiagram (Approximate the percentages to the nearest integer)

 Year Permanent Roads       ( Lakh km.) Temporary Roads       ( Lakh km.) 2000-2001 14 10 2001-2002 15 11 2003-2004 17 13 2007-2008 20 19

#### Balbharati solutions for Class 9 Chapter 7 Exercise Practice set 7.2 [Page 113]

Practice set 7.2 | Q 1.1 | Page 113

Classify following information as primary or secondary data.

Information of attendance of every student collected by visiting every class in a school.

Practice set 7.2 | Q 1.2 | Page 113

Classify following information as primary or secondary data.

The information of heights of students was gathered from school records and sent to the head office, as it was to be sent urgently.

Practice set 7.2 | Q 1.3 | Page 113

Classify following information as primary or secondary data.

In the village Nandpur, the information collected from every house regarding students not attending school.

Practice set 7.2 | Q 1.4 | Page 113

Classify following information as primary or secondary data

For science project, information of trees gathered by visiting a forest.

#### Balbharati solutions for Class 9 Chapter 7 Exercise Practice set 7.3 [Pages 118 - 119]

Practice set 7.3 | Q 1 | Page 118

For class interval 20-25 write the lower class limit and the upper class limit.

Practice set 7.3 | Q 2 | Page 118

Find the class-mark of the class 35-40.

Practice set 7.3 | Q 3 | Page 118

If class mark is 10 and class width is 6 then find the class.

Practice set 7.3 | Q 4 | Page 118

Complete the Following Table.

 Classes (age) Tally marks Frequency (No. of students) 12-13 ............. 13-14 ............. 14-15 ............. ............. 15-16 ............. N = ∑ f = 35
Practice set 7.3 | Q 5 | Page 118
In a ‘tree plantation’ project of a certain school there are 45 students of 'Harit Sena.' The record of trees planted by each student is given below :
3, 5, 7, 6, 4, 3, 5, 4, 3, 5, 4, 7, 5 , 3, 6, 6, 5, 3, 4, 5, 7, 3, 5, 6, 4, 4, 3, 5, 6, 6, 4, 3, 5, 7, 3, 4, 5, 7, 6, 4, 3, 5, 4, 4, 7.
Prepare a frequency distribution table of the data.
Practice set 7.3 | Q 6 | Page 118

The value of π upto 50 decimal places is given below :
3.14159265358979323846264338327950288419716939937510  From this information prepare an ungrouped frequency distribution table of digits appearing after the decimal point.

Practice set 7.3 | Q 7.1 | Page 119

In the tables given below, class-mark and frequencies is given. Construct the frequency tables taking inclusive and exclusive classes.

 Class width Frequency 5 3 15 9 25 15 35 13
Practice set 7.3 | Q 7.2 | Page 118

In the tables given below, class-mark and frequencies is given. Construct the frequency tables taking inclusive and exclusive classes

 Class width Frequency 22 6 24 7 26 13 28 4
Practice set 7.3 | Q 8 | Page 119
In a school, 46 students of 9th standard, were told to measure the lengths of the pencilsin their compass-boxes in centimeters. The data collected was as follows.
16, 15,  7, 4.5,   8.5,  5.5,  5, 6.5, 6, 10, 12, 13, 4.5,  4.9,   16,  11, 9.2,   7.3,  11.4,  12.7,  13.9,  16, 5.5,  9.9,   8.4,   11.4,  13.1,   15,  4.8,   10,  7.5,   8.5,   6.5,   7.2,   4.5,   5.7,   16,   5.7,   6.9,   8.9,   9.2,   10.2,   12.3,   13.7, 14.5,   10
By taking inclusive classes 0-5, 5-10, 10-15.... prepare a grouped frequency distribution table.
Practice set 7.3 | Q 9 | Page 118
In a village, the milk was collected from 50 milkmen at a collection center in litres as given below :
27,   75, 5,  99, 70, 12, 15, 20, 30, 35, 45, 80, 77,  90, 92, 72, 4,  33, 22, 15, 20, 28, 29, 14, 16, 20, 72, 81,  85,  10,  16,  9, 25,  23,  26,  46, 55,  56, 66, 67, 51, 57, 44, 43, 6,  65, 42, 36, 7, 35.
By taking suitable classes, prepare grouped frequency distribution table.
Practice set 7.3 | Q 10 | Page 118
38 people donated to an organisation working for differently abled persons. The amount in rupees were as follows :
101,   500,   401,   201,   301,   160,   210,   125,  175,  190,  450,  151, 101,  351,  251,  451,  151, 260, 360, 410, 150, 125, 161, 195, 351, 170,  225, 260, 290, 310, 360, 425, 420, 100, 105, 170, 250, 100.
(i) By taking classes 100-149, 150-199, 200-249... prepare grouped frequency distribution table.
(ii) From the table, find the number of people who donated rupees 350 or more.

#### Balbharati solutions for Class 9 Chapter 7 Exercise Practice set 7.4 [Pages 121 - 122]

Practice set 7.4 | Q 1 | Page 121

Complete the following cumulative freuqency table :

 Class(Height in cm) Frequency(No. of students) Less thantype frequency 150 - 153 05 05 153 - 156 07 05 + ....... = ........ 156 - 159 15 ....... + 15 = ......... 159 - 162 10 ........ + ........ = 37 162 - 165 05 37 + 5 = 42 165 - 168 03 ......... + ....... = 45 Total N = 45
Practice set 7.4 | Q 2 | Page 122

Complete the following Cumulative Frequency Table :

 Class (Monthly income in Rs.) Frequency (No. of  individuals) More than or equal to type cumulative           frequency 1000 - 5000 45 ............. 5000 - 10000 19 ............. 10000 -15000 16 ............. 15000-20000 02 ............. 20000-25000 05 ............. Total N=87
Practice set 7.4 | Q 3 | Page 122

The data is given for 62 students in a certain class regarding their mathematics marks out of 100. Take the classes 0-10, 10-20.. and prepare frequency distribution table and cumulative frequency table more than or equal to type.
55, 60, 81, 90, 45, 65,  45, 52, 30,  85,  20, 10, 75, 95, 09, 20, 25, 39,  45, 50, 78,  70,  46, 64, 42, 58, 31, 82, 27, 11,  78, 97, 07,  22,  2  36, 35, 40, 75, 80, 47, 69,  48, 59, 32,  83,  23, 17, 77, 45, 05, 23, 37, 38,  35, 25, 46,  57,  68, 45, 47, 49.

From the prepared table, answer the following questions :
(i)  How many students obtained marks 40 or above 40 ?
(ii)  How many students obtained marks 90 or above 90 ?
(iii)  How many students obtained marks 60 or above 60 ?
(iv)  What is the cumulative frequency of equal to or more than type of the class 0-10?
Practice set 7.4 | Q 4 | Page 122

The data is given for 62 students in a certain class regarding their mathematics marks out of 100. Take the classes 0-10, 10-20.. and
prepare less than type cumulative frequency table and answer the following questions.
55, 60, 81, 90, 45, 65,  45, 52, 30,  85,  20, 10, 75, 95, 09, 20, 25, 39,  45, 50, 78,  70,  46, 64, 42, 58, 31, 82, 27, 11,  78, 97, 07,  22,  2  36, 35, 40, 75, 80, 47, 69,  48, 59, 32,  83,  23, 17, 77, 45, 05, 23, 37, 38,  35, 25, 46,  57,  68, 45, 47, 49.
(i)  How many students obtained less than 40 marks ?
(ii)  How many students obtained less than 10 marks ?
(iii)  How many students obtained less than 60 marks ?
(iv) Find the cumulative frequency of the class 50-60.

#### Balbharati solutions for Class 9 Chapter 7 Exercise Practice set 7.5 [Page 125]

Practice set 7.5 | Q 1 | Page 125

Yield of soyabean per acre in quintal in Mukund's field for 7 years was 10, 7, 5, 3, 9, 6, 9. Find the mean of yield per acre.

Practice set 7.5 | Q 2 | Page 125

Find the median of the observations, 59, 75, 68, 70, 74, 75, 80.

Practice set 7.5 | Q 3 | Page 125

The marks (out of 100) obtained by 7 students in Mathematics' examination are given below. Find the mode for these marks.
99, 100, 95, 100, 100, 60, 90

Practice set 7.5 | Q 4 | Page 125
The monthly salaries in rupees of 30 workers in a factory are given below.
5000, 7000, 3000, 4000, 4000, 3000, 3000, 3000, 8000, 4000,
4000, 9000, 3000, 5000, 5000, 4000, 4000, 3000, 5000, 5000,
6000, 8000, 3000, 3000, 6000, 7000, 7000, 6000, 6000, 4000
From the above data find the mean of monthly salary.
Practice set 7.5 | Q 5 | Page 125
In a basket there are 10 tomatoes. The weight of each of these tomatoes in grams is as follows:
60, 70, 90, 95, 50, 65, 70, 80, 85, 95.
Find the median of the weights of tomatoes.
Practice set 7.5 | Q 6 | Page 125
A hockey player has scored following number of goals in 9 matches.
5, 4, 0, 2, 2, 4, 4, 3, 3
Find the mean, median and mode of the data.
Practice set 7.5 | Q 7 | Page 125

The calculated mean of 50 observations was 80. It was later discovered that observation 19 was recorded by mistake as 91. What was the correct mean?

Practice set 7.5 | Q 8 | Page 125
Following 10 observations are arranged in ascending order as follows.
2, 3, 5, 9, + 1, x + 3, 14, 16, 19, 20
If the median of the data is 11, find the value of x
Practice set 7.5 | Q 9 | Page 125

The mean of 35 observations is 20, out of which mean of first 18 observations is 15 and mean of last 18 observation is 25. Find the 18th observation.

Practice set 7.5 | Q 10 | Page 125

The mean of 5 observations is 50. One of the observations was removed from the data, hence the mean became 45. Find the observation which was removed.

Practice set 7.5 | Q 11 | Page 125

There are 40 students in a class, out of them 15 are boys. The mean of marks obtained by boys is 33 and that for girls is 35. Find out the mean of all students in the class.

Practice set 7.5 | Q 12 | Page 125
The weights of 10 students (in kg) are given below :
40, 35, 42, 43, 37, 35, 37, 37, 42, 37.
Find the mode of the data
Practice set 7.5 | Q 13 | Page 125

In the following table, the information is given about the number of families and the siblings in the families less than 14 years of age. Find the mode of the data

 No. of siblings 1 2 3 4 Families 15 25 5 5
Practice set 7.5 | Q 14 | Page 125

Find the mode of the following data.

 Marks 35 36 37 38 39 40 No of Student 09 07 09 04 04 02

#### Balbharati solutions for Class 9 Chapter 7 Exercise Problem Set 7 [Pages 126 - 217]

Problem Set 7 | Q 1.01 | Page 126

Which of the following data is not primary ?
(A) By visiting a certain class, gathering information about attendence of students.
(B) By actual visit to homes, to find number of family members.
(C) To get information regarding plantation of soyabean done by each farmer
from the village Talathi.
(D) Review the cleanliness status of canals by actually visitiing them.

Problem Set 7 | Q 1.02 | Page 126

What is the upper class limit for the class 25-35 ?

• 25

• 35

• 60

• 30

Problem Set 7 | Q 1.03 | Page 126

What is the class-mark of class 25-35 ?

• 25

• 35

• 60

• 30

Problem Set 7 | Q 1.04 | Page 126

If the classes are 0-10, 10-20, 20-30... then in which class should the observation 10 be included ?

• 0 - 10

• 10 - 20

• 0 - 10 and 10 - 20 in these 2 classes

• 20 - 30

Problem Set 7 | Q 1.05 | Page 126

If barX is the mean of  X_1, X_2 ...............X_n and  bar Y is the mean of Y_1, Y_2.................... Y_n and  barZ is the mean X_1, X_2.............. X_n, Y_1, Y_2, .........................Y_n then Z ?

• (bar X  + bar Y) / 2

• bar X + bar Y

• (bar X  + bar Y) / n

•  (barX + bar Y) /(2n)

Problem Set 7 | Q 1.06 | Page 126

The mean of five numbers is 80, out of which mean of 4 numbers is 46, find the 5th number

• 4

• 20

• 434

• 66

• None of the above

Problem Set 7 | Q 1.07 | Page 126

Mean of 100 observations is 40. The 9th observation is 30. If this is replaced by 70 keeping all other observations same, find the new mean.

• 40.6

• 40.4

• 40.3

• 40.7

Problem Set 7 | Q 1.08 | Page 126

What is the the mode of 19, 19, 15, 20, 25, 15, 20, 15?

• 15

• 20

• 19

• 25

Problem Set 7 | Q 1.09 | Page 126

What is the median of 7, 10, 7, 5, 9, 10 ?

• 7

• 9

• 8

• 10

Problem Set 7 | Q 1.1 | Page 126

From following table, what is the cumulative frequency of less than type for the class 30-40 ?

 Class 0-10 10-20 20-30 30-40 40-50 Frequency 7 3 12 13 2
• 13

• 15

• 35

• 22

Problem Set 7 | Q 2 | Page 127

The mean salary of 20 workers is Rs.10,250. If the salary of office superintendent is added, the mean will increase by Rs.750. Find the salary of the office superintendent.

Problem Set 7 | Q 3 | Page 127

The mean of nine numbers is 77. If one more number is added to it then the mean increases by 5. Find the number added in the data.

Problem Set 7 | Q 4 | Page 127

The monthly maximum temperature of a city is given in degree celcius in the following data. By taking suitable classes, prepare the grouped frequency distribution table
29.2, 29.0, 28.1, 28.5, 32.9, 29.2, 34.2, 36.8, 32.0, 31.0, 30.5, 30.0, 33, 32.5, 35.5, 34.0, 32.9, 31.5, 30.3, 31.4, 30.3, 34.7, 35.0, 32.5, 33.5, 29.0, 29.5, 29.9, 33.2, 30.2
From the table, answer the following questions.
(i)  For how many days the maximum temperature was less than 34oC ?
(ii)  For how many days the maximum temperature was 34oC or more than 34oC ?

Problem Set 7 | Q 5 | Page 217

If the mean of the following data is 20.2, then find the value of p.

 x_i 10 15 20 25 30 f_i 6 8 p 10 6
Problem Set 7 | Q 6 | Page 127

There are 68 students of 9th standard from model Highschool, Nandpur. They have scored following marks out of 80, in written exam of mathematics.
70,  50,   60,  66,  45,  46,   38,   30,  40,  47,   56,   68,  80,  79,   39,   43,  57, 61,   51, 32,   42, 43,   75, 43, 36,   37,   61,   71,   32, 40,   45,   32, 36,   42,   43, 55, 56, 62,   66,   72,   73,   78,   36,   46,  47,   52,   68,   78, 80, 49,   59, 69,   65,   35,   46,   56,   57,   60,  36,  37, 45,   42,   70, 37,   45,  66,   56,   47
By taking classes 30-40, 40-50, .... prepare the less than type cumulative frequency table

Using the table, answer the following questions :
(i)  How many students, have scored marks less than 80 ?
(ii)  How many students have scored marks less than 40 ?
(iii)  How many students have scored marks less than 60 ?

## Chapter 7: Statistics

Practice set 7.1Practice set 7.2Practice set 7.3Practice set 7.4Practice set 7.5Problem Set 7

## Balbharati solutions for Class 9 Algebra chapter 7 - Statistics

Balbharati solutions for Class 9 chapter 7 (Statistics) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the Maharashtra State Board Balbharati Class 9 Mathematics 1 Algebra solutions in a manner that help students grasp basic concepts better and faster.

Further, we at Shaalaa.com provide such solutions so that students can prepare for written exams. Balbharati textbook solutions can be a core help for self-study and acts as a perfect self-help guidance for students.

Concepts covered in Class 9 Algebra chapter 7 Statistics are Introduction of Statistics, Bar Diagrams, Collection of Data, Frequency Distribution Table, Measures of Central Tendency, Cumulative Frequency Table.

Using Balbharati Class 9 solutions Statistics exercise by students are an easy way to prepare for the exams, as they involve solutions arranged chapter-wise also page wise. The questions involved in Balbharati Solutions are important questions that can be asked in the final exam. Maximum students of Maharashtra State Board Class 9 prefer Balbharati Textbook Solutions to score more in exam.

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