# How to Calculate Deciles Statistics - Tutorial

## Learn How to Calculate Deciles Statistics - Definition, Formula, Example

##### Definition:

A system of dividing the given random distribution of the data or values in a series into ten groups of similar frequency is known as deciles.

#### Formula: ###### Where,

Li = Lower limit of the decile class N = Sum of the absolute frequency Fi-1 = Absolute frequency lies below the decile class ai = Width of the class containing the decile class

##### Example:

Find the deciles for the following data. 3, 15, 24, 28, 33, 35, 38, 42, 43, 38, 36, 34, 29, 25, 17, 7, 34, 36, 39, 44, 31, 26, 20, 11, 13, 22, 27, 47, 39, 37, 34, 32, 35, 28, 38, 41, 48, 15, 32, 60, 56, 13.

##### Given,

Data = 3, 15, 24, 28, 33, 35, 38, 42, 43, 38, 36, 34, 29, 25, 17, 7, 34, 36, 39, 44, 31, 26, 20, 11, 13, 22, 27, 47, 39, 37, 34, 32, 35, 28, 38, 41, 48, 15, 32, 60, 56, 13. N = 42

##### To Find,

Deciles Statistics

##### Solution:
###### Step 1:

Let us calculate the Cumulative Frequency value for the given data, Cumulative Frequency is calculated using the formula, Fi = Fi-1 + fi

ClassFrequency fiCumulative Frequency Fi
3 - 1022
10 - 1757
17 - 24310
24 - 31717
31 - 381229
38 - 45938
45 - 52240
52 - 59141
59 - 66142

In the above table, class denotes the range of values Frequency (fi) denotes the number of values between the class range from the given data. For Ex: Class range 3-10 represents that there are two values i.e. 3 and 7 in the given data

###### Step 2:

Now let us calculate the deciles for each class. Calculation of First Decile: First, consider k = 1 Since the value is 4.2, it is present inside the class range [3, 10)] Now, substitute the values in the formula, D1 = 3 + (4.2-0) / 2 * 7 D1 = 3+2.1*7 D1 = 17.7

###### Step 3:

Calculation of Second Decile: Consider, k = 2 K.N / 10 = 2*42 / 10 = 8.4 The value is 8.4. So, it is present inside the class range [10, 17)] Substitute the values in the formula, D2 = 10 + (8.4-2) / 5 * 7 D2 = 3+1.28*7 D2 = 18.96 Similarly, calculate the deciles for rest of the seven classes.