The following table gives heights (in c m ) of 8 girls and 8 boys. Boys 182 153 161 186 152 171 163 137 Girls 138 168 152 172 149 155 123 150 Find the range of the height of boys and girls

The given table is, Boys 182 153 161 186 152 171 163 137 Girls 138 168 152 172 149 155 123 150 We know that, The difference between the two extreme values gives us the idea about the spread of the observations, and it is called the range of the observations. Range = Highest observation - Lowest observation Here, Highest observation of height (in c m ) for boys = 186 Highest observation of height (in c m ) for girls = 172 Lowest observation of height (in c m ) for boys = 137 Lowest observation of height (in c m ) for girls = 123 Therefore, the range of heights of boys (in c m ) = 186 - 137 = 49 And, the range of heights of boys (in c m ) = 172 - 123 = 49 Hence, the range of the heights of the boys and the girls is 49 c m and 49 c m each.

The following table gives heights (in c m ) of 8 girls and 8 boys. Boys 182 153 161 186 152 171 163 137 Girls 138 168 152 172 149 155 123 150 Find the new mean of the heights of boys if a boy of height 180 c m also joins in the group.

The given table is, Boys 182 153 161 186 152 171 163 137 Girls 138 168 152 172 149 155 123 150 Now, a boy of height 180 c m joins the group. So the sum of the heights (in c m ) of boys = 182 + 153 + 161 + 186 + 152 + 171 + 163 + 137 + 180 = 1485 We know that, Mean = S u m o f a l l t h e o b s e r v a t i o n s T o t a l n u m b e r o f o b s e r v a t i o n s Therefore, the mean height of boys = 1485 9 = 165 Hence, the mean height of the boys is 165 c m .

The number of boys and girls studying in six classes is given below. Represent the data using a double bar graph. Class V I V I I V I I I I X X X I Number of boys 150 120 100 90 80 60 Number of girls 100 90 80 80 60 40

The given table is, Class V I V I I V I I I I X X X I Number of boys 150 120 100 90 80 60 Number of girls 100 90 80 80 60 40 A double bar graph is the graphical representation of grouped data. In a double bar graph, two rectangular bars are drawn for each category. These two bars represent the two given parameters for each category. The x - axis is used to represent the different items/categories. The y - axis is used to represent the two parameters. The two bars are plotted for each item/category with respect to the y - axis. The bars are plotted up to a height that is proportional to the numerical value provided in the data set information. Draw a horizontal line O X as x - axis and vertical line O Y as y - axis. We mark the horizontal axis as "Class" and the vertical axis as "Number of students". Along x - axis we choose the bar of uniform(equal) width, with a uniform gap between them. Along y - axis we choose 1 division = 10 students. All the bars should be of the same width and the same space should be left between the consecutive bars. The graph is as follows:

The marks obtained out of 100 by 5 students in Mathematics and Physics are given below. Draw a double bar graph to represent the data. Students Alka Babita Charlie Siddique Uma Mathematics 92 90 86 98 85 Physics 94 94 96 96 80

The given table is, Students Alka Babita Charlie Siddique Uma Mathematics 92 90 86 98 85 Physics 94 94 96 96 80 A double bar graph is the graphical representation of grouped data. In a double bar graph, two rectangular bars are drawn for each category. These two bars represent the two given parameters for each category. The x - axis is used to represent the different items/categories. The y - axis is used to represent the two parameters. The two bars are plotted for each item/category with respect to the y - axis. The bars are plotted up to a height that is proportional to the numerical value provided in the data set information. Draw a horizontal line O X as x - axis and vertical line O Y as y - axis. We mark the vertical axis as "Numbers obtained" and the horizontal axis as "Name of the students". Along x - axis we choose the bar of uniform(equal) width, with a uniform gap between them. Along y - axis we choose 1 division = 10 students. All the bars should be of the same width and the same space should be left between the consecutive bars. The graph is as follows:

E M B I B E

Maths Express 7>Chapter 17 - Data Handling>Revision time

Revision time

Author:Jayashree Vipin

Jayashree Vipin Mathematics Solutions for Exercise - Revision time

Simple step-by-step solutions to Revision time questions of Data Handling from Maths Express 7. Also get 3D topic explainers, cheat sheets, and unlimited doubts solving on EMBIBE.

Questions from Revision time with Hints & Solutions

MEDIUM

7th CBSE

IMPORTANT

Maths Express 7>Chapter 17 - Data Handling>Revision time>Q 3

The following table gives heights (in $c m$ ) of $8$ girls and $8$ boys.

Boys	$182$	$153$	$161$	$186$	$152$	$171$	$163$	$137$
Girls	$138$	$168$	$152$	$172$	$149$	$155$	$123$	$150$

Find the range of the height of boys and girls

MEDIUM

7th CBSE

IMPORTANT

Maths Express 7>Chapter 17 - Data Handling>Revision time>Q 4

The following table gives heights (in $c m$ ) of $8$ girls and $8$ boys.

Boys	$182$	$153$	$161$	$186$	$152$	$171$	$163$	$137$
Girls	$138$	$168$	$152$	$172$	$149$	$155$	$123$	$150$

Find the new mean of the heights of boys if a boy of height $180 c m$ also joins in the group.

MEDIUM

7th CBSE

IMPORTANT

Maths Express 7>Chapter 17 - Data Handling>Revision time>Q 5

Name the representative observation which occurs most frequently.

MEDIUM

7th CBSE

IMPORTANT

Maths Express 7>Chapter 17 - Data Handling>Revision time>Q 6

Name the middle value of the data.

EASY

7th CBSE

IMPORTANT

Maths Express 7>Chapter 17 - Data Handling>Revision time>Q 7

Find the range of the following values.

$37, 56, 35, 61, 32$

MEDIUM

7th CBSE

IMPORTANT

Maths Express 7>Chapter 17 - Data Handling>Revision time>Q 8

Number of new students enroled in the primary classes of a private school for a particular academic year is given below. Represent the data on a bar graph.