# Statistics Class-8 RS Aggarwal ICSE Goyal Brothers Prakashan

**Statistics Class-8 RS Aggarwal** ICSE Goyal Brothers Prakashan Solutions Chapter-25. We provide step by step Solutions of Exercise / lesson-25 **Statistics**** **for ICSE **Class-8 RS** **Aggarwal** Mathematics.

Our Solutions contain all type Questions of Exe-25 with Notes to develop skill and confidence. Visit official Website CISCE for detail information about ICSE Board Class-8 Mathematics.

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### Notes on **Statistics **

**Introduction to Statistics**

– A study dealing with the collection, presentation and interpretation and analysis of data is called as statistics

**Data**

- Facts /figures numerical or otherwise collected for a definite purpose is called as data.
- data collected first-hand data:- Primary
- Secondary data: Data collected from a source that already had data stored

**Frequency**

– The number of times a particular instance occurs is called frequency in statistics.

**Ungrouped data**

Ungrouped data is data in its original or raw form. The observations are not classified in groups.

**Grouped data**

In grouped data, observations are organized in groups

**Class Interval**

- The size of the class into which a particular data is divided.
- E.g divisions on a histogram or bar graph.
**Class width**= upper class limit – lower class limit

**Regular and Irregular class interval**

- Regular class interval: When the class intervals are equal or of the same sizes.
- E.g 0-10, 10-20, 20-30…..
- Irregular class interval: When the class intervals are of varying sizes.
- E.g 0-35, 35-45, 45-55,

**Frequency table**

– A frequency table or distribution shows the occurrence of a particular variable in a tabular form.

**Sorting**

- Raw data needs to be sorted in order to carry out operations.-
- Sorting ⇒ ascending order or descending order

**Ungrouped frequency table**

– When the frequency of each class interval is not arranged or organised in any manner

**Grouped frequency table**

– The frequencies of the corresponding class intervals are organised or arranged in a particular manner, either ascending or descending.

**Exe-25** ,**Statistics Class-8 RS Aggarwal** ICSE Goyal Brothers Prakashan Solutions

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