## CBSE Class 10 Maths Chapter 14 – Statistics – Free PDF Download

Free PDF download of Class 10 Maths Chapter 14 – Statistics Revision Notes & Short Key-notes prepared by expert Mathematics teachers from latest edition of CBSE(NCERT) books.

You can also Download __Maths NCERT Solutions Class 10__ to help you to revise complete Syllabus and score more marks in your examinations.

**CBSE Class 10 Maths Revision Notes Chapter 14 Statistics**

- Mean of Grouped Data
- Mode of Grouped Data
- Median of Grouped Data
- Graphical Representation of CF
- Miscellaneous Questions

1. **Mean** : The mean for grouped data can be found by :

(i) The direct method =

(ii) The assumed mean method

Where a = Provisional mean

(iii) The step deviation method

2. **Mode** : The mode for the grouped data can be found by using the formula :

= lower limit of the modal class.

= frequency of the modal class.

= frequency of the preceding class of the modal class.

= frequency of the succeeding class of the modal class.

h = size of the class interval.

Modal class – class interval with highest frequency.

3. **Median** : Median of continuous series is:

(i) term (if number of terms are odd)

(ii) (if number of terms are even]

(iii) The median for the grouped data can be found by using the formula :

= lower limit of the median class.

n = number of observations.

Cf = cumulative frequency of class interval preceding the median class.

f = frequency of median class.

h = class size.

4.**Empirical Formula **: Mode = 3 median – 2 mean.

5.**Cumulative frequency curve or an Ogive **:

(i) Ogive is the graphical representation of the cumulative frequency distribution.

(ii) Less than type Ogive :

• Construct a cumulative frequency table.

• Mark the upper class limit on the x-axis.

(iii) More than type Ogive :

• Construct a frequency table.

• Mark the lower class limit on the x-axis.

(iv) To obtain the median of frequency distribution from the graph :

• Locate point of intersection of less than type Ogive and more than type Ogive :

Draw a perpendicular from this point on x-axis.

• The point at which it cuts the x-axis gives us the median.