NCERT Class 9 Solutions: Statistics (Chapter 14) Exercise 14.3-Part 3 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Q-7 The runs scored by two teams A and B on the first 60 balls in a cricket match are given below:

Runs Scored by Two Teams in Cricket Match
Number of ballsTeams ATeam B
25
16
82
910
45
56
63
104
68
210

Represent the table data of both the teams on the same graph by frequency polygons.

[Hint: First make the class intervals continuous.]

Solution:

Convert to continuous frequency distribution:

Difference between lower limit of class and upper limit of preceding class:

Hence, added to each upper class limit and subtract from the lower class limits.

Class marks

Obtain distribution is given as under:

Obtain Continuous Frequency Distribution
Number of ballsClass marksTeam ATeam B
3.525
9.516
15.582
21.5910
27.545
33.545
39.563
45.5104
51.568
57.5210

Class mark on x-axis and number of balls on y-axis

Drawn the graph:

Chart Representing the Data

Q-8 A random survey of the number of children of various age groups playing in park was found as follows:

Draw a Histogram to Represent the Data of Table
Age (in years)Number of children
5
3
6
12
9
10
4

Draw a histogram to represent the data above.

Solution:

As given frequency data in class size are different.

So, we calculate adjusted frequency for each class using formula:

Adjusted frequency

Here, minimum class size

Find the Adjusted Frequency to Draw Histogram
Age (In year)Frequency (number of children)Width of classesAdjusted Frequency
51
31
62
122
93
105
42

In below chart age of children on x-axis

Proportion of children per 1 year interval on y-axis

Chart Representing the Data

Developed by: