ORGANISING THE DATA. What is data ?. Data is a collection of facts , such as values or Measurements. It can be numbers, words , measurements, observations or even just description of things. why do we organize data?.
“a picture is worth a thousand words”
The advantages of organizing data is that, we
get an overall view of the result of our data and through this , one can easily interpret the data and can make decisions or policies.
Aman weighs 78 kg, is 172cm tall and has scored 91% marks, Rupal has scored 92% , is 153 cm tall and weighs 54 kg ; Yashika- height 146cm , scored 86 % , weight 43kg,……….
If one has to continue writing for 20 students, it would be extremely cumbersome and no one would have the patience to read the whole data. It would be difficult to interpret .
Here , we analyzed only the weight of the students. The least weight is 42 kg whereas the maximum weight is 87 kg.
Example : We have a frequency distribution which consists of the blood groups of 50 people , which is given below:
Class mark : Class mark is the middle value of the class interval and is calculated as ,
Step 1 : Find the minimum and the maximum values in the data .
Step 2 : Find the range = Maximum value – Minimum value.
Step 3 : Decide upon the class size h , of each class interval.
Usually , class size is multiple of 5. Otherwise it can be
any positive number. It depends on the nature and size of
Step 4: Find the number of class intervals by using the formula,
Number of class intervals = least positive integer ≥