LEARN MATH STEP BY STEP THROUGH VERY EASY PROCESS

RAW OR UNGROUPED DATA

**Raw or Ungrouped Data –**

**The data
obtained in original form are called “raw data or ungrouped data”.**

__Example –__
The marks obtained by 30 students in a class in a certain examination are given
below-

**25, 8, 37,
16, 45, 40, 29, 12, 42, 40, 28, 32, 43, 42, 41, 25, 15, 16, 26, 20, 14, 36, 33,
24, 25, 35, 11, 30, 47, 48.**

**Above date
is raw data.**

**Array :**-**An arrangement of raw data in
ascending or descending order of magnitude is called an “array”. Arranging the
marks of 30 students in ascending order, we get the following array.**

**8, 11, 12,
14, 15, 16, 16, 20, 24, 25, 25, 25, 26, 28, 29, 30, 32, 33, 35, 36, 37, 40, 40,
41, 42, 42, 43, 45, 47, 48.**

**To
prepare a Frequency Distribution Table for Raw data using Tally Marks:**

**We take
each observation from the data, one at a time, and indicate the frequency (the
number of times the observation has occurred in the data) by small lines is to
be considered or known as Tally Marks. For convenience, we write tally
marks in bunches of five (5), the fifth one crossing the fourth diagonally. In
the table so formed, the sum of all the frequencies is equal to the total
number of observations in given data.**

__Example-__ The sale of dress of various sizes at a shop, on a particular day is given below –

**9 11 22 20 14 16 8 9 10 12 11 22 18 16 18 8 11 22 16 10 20 14 8 9 11 12 22 8 8**

**22 16 14 18 11 12 22 16 20 9 10 14 11 22 9 11 22 16 10 12 22 8 11 9 14 8 9 10 12**

**The above data is clearly raw data. From this data, we construct a frequency table, as given below –**

**Frequency Table -**