For what data frequency must be arranged
Answers
Frequency distribution in statistics provides the information of the number of occurrences (frequency) of distinct values distributed within a given period of time or interval, in a list, table, or graphical representation. Grouped and Ungrouped are two types of Frequency Distribution. Data is a collection of numbers or values and it must be organized for it to be useful. Let us take a look at data and its frequency distribution.
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Data
Any bit of information that is expressed in a value or numerical number is data. For example, the marks you scored in your Math exam is data, and the number of cars that pass through a bridge in a day is also data. Data is basically a collection of information, measurements or observations.
Raw data is an initial collection of information. This information has not yet been organized. After the very first step of data collection, you will get raw data. For example, we go around and ask a group of five friends their favourite colour. The answers are Blue, Green, Blue, Red, and Red. This collection of information is the raw data.
Then there is discrete data and continuous data. Discrete data is that which is recorded in whole numbers, like the number of children in a school or number of tigers in a zoo. It cannot be in decimals or fractions. Continuous data need not be in whole numbers, it can be in decimals. Examples are the temperature in a city for a week, your percentage of marks for the last exam etc.
Frequency
The frequency of any value is the number of times that value appears in a data set. So from the above examples of colours, we can say two children like the colour blue, so its frequency is two. So to make meaning of the raw data, we must organize. And finding out the frequency of the data values is how this organisation is done.
Frequency Distribution
Many times it is not easy or feasible to find the frequency of data from a very large dataset. So to make sense of the data we make a frequency table and graphs. Let us take the example of the heights of ten students in cms.
Frequency Distribution Table
139, 145, 150, 145, 136, 150, 152, 144, 138, 138
Frequency distribution table
This frequency table will help us make better sense of the data given. Also when the data set is too big (say if we were dealing with 100 students) we use tally marks for counting. It makes the task more organised and easy. Below is an example of how we use tally marks.
Frequency distribution
Frequency Distribution Graph
Using the same above example we can make the following graph:
Frequency-distribution-graph