notes
Collecting Data:
Temperatures of cities as on 20.6.2006 |
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City |
Max. |
Min. |
| Ahmedabad | 38°C | 29°C |
| Amritsar | 37°C | 26°C |
| Bangalore | 28°C | 21°C |
| Chennai | 36°C | 27°C |
| Delhi | 38°C | 28°C |
| Jaipur | 39°C | 29°C |
| Jammu | 41°C | 26°C |
| Mumbai | 32°C |
27°C |
What do these collections of data tell you?
The data about the temperatures of cities can tell us many things, For example, you can say that the highest maximum temperature was in Jammu on 20.06.2006 but it cannot tell us the city which had the highest maximum temperature during the year. To find that, we need to collect data regarding the highest maximum temperature reached in each of these cities during the year. In that case, the temperature chart of one particular date of the year, as given in the table will not be sufficient. This shows that a given collection of data may not give us specific information related to that data.
For this, we need to collect data keeping in mind that specific information. In the above case, the specific information needed by us was about the highest maximum temperature of the cities during the year, which we could not get from the Table. Thus, before collecting data, we need to know what we would use it for.
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When the information was collected by the investigator herself or himself with a definite objective in her or his mind, the data obtained is called primary data.
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When the information was gathered from a source which already had the information stored, the data obtained is called secondary data.
Such data, which has been collected by someone else in another context, needs to be used with great care ensuring that the source is reliable.
