What is Data?
Data can be defined as a systematic record of a particular quantity. It is the different values of that quantity represented together in a set. It is a collection of facts and figures to be used for a specific purpose such as a survey or analysis. When arranged in an organized form, it can be called information.
What are grouped data and ungrouped data?
Grouped data means the data (or information) given in the form of class intervals such as 0-20, 20-40, and so on. Ungrouped data is defined as the data given as individual points (i.e. values or numbers) such as 15, 63, 34, 20, 25, and so on.
What is a grouped data example?
Suppose we have data ranges from 0 to 50 like 2, 17, 0, 1, 8, 19, 43, 2, 1, 32, and so on. In this case, we can group the data into classes such as 0-10, 10-20,…,40-50. This is a simple example of grouped data.
What are the advantages of grouping data?
The main advantages of grouping data are:
- Assist us in concentrating on essential subgroups mainly and overlooks trivial ones.
- Helps in increasing the efficiency and correctness of the required estimation.
How do you group data into a class?
An important technique used for grouping the given data is tally marks. With the help of a tally marks table, it is possible to convert the data into classes without any confusion. Then find the height (or size) of the class interval by dividing the difference between the highest and the least data value by the number of classes we want (in the case of the decimal value, the nearest whole number defines the class size).
How many classes can a grouped data have?
For ideal grouped data, it is suggested to have the number of class intervals as a minimum of 5 and a maximum of 20. But we can also observe grouped data with less than 5 class intervals in many situations.
Types of Data
Data may be qualitative or quantitative.
Qualitative Data:
They represent some characteristics or attributes. They depict descriptions that may be observed but cannot be computed or calculated.
For example, data on traits such as intelligence, honesty, wisdom, cleanliness, and creativity collected using the students of your class sample would be classified as qualitative. They are more exploratory than conclusive in nature.
Quantitative Data:
These can be measured and not simply observed. They can be numerically represented and calculations can be performed on them.
For example, data on the number of students playing different sports from your class estimate how many of the total students play which sport. This information is numerical and can be classified as quantitative.
Data Collection
Depending on the source, it can classify as primary data or secondary data. Let us take a look at them both.
Primary Data
These are the data that are collected for the first time by an investigator for a specific purpose. Primary data are ‘pure’ in the sense that no statistical operations have been performed on them and they are original. An example of primary data is the Census of Pakistan.
Secondary Data
They are the data that are sourced from someplace that has originally collected it. This means that this kind of data has already been collected by some researchers or investigators in the past and is available either in published or unpublished form. This information is impure as statistical operations may have been performed on them already.