Embedded Files
Welcome to A-level ICT
Often data is encoded - each data item is represented by a code.
Examples :
Each item in a supermarket is coded by a barcode number.
Each book in a library has an ISBN number.
Each branch of each High Street Bank has an individual branch sort code
Eg. 51-81-26Each pupil's gender is recorded on a school's database as 'M' for male or 'F' for female.
Country codes for Olympic athletes may be GB, US, F etc..
When the data is input, the codes are used.
Reasons for encoding data:
Reasons for encoding data:
The data is easier and quicker to enter because the codes are shorter.
Validation of the data is easier.
Reduces the amount of hard disk space / less memory required - NOT less space
Lessens the chance of entry errors / easier to validate / greater consistency.
Faster to search.
Validation is the checking of data to make sure it is sensible data.
Problems with encoding data:
Problems with encoding data:
Encoding can coarsen data and the loss of precision must be weighed against its advantages, e.g. Hair colour survey light brown, mousey, dark brown would all be classified as brown because all the categories are not
present.
Subjective judgements e.g. someone may be asked was that mea l‘Excellent’, ‘Very Good’, ‘Good’, or ‘Poor’. One person’s excellent meal is only a good meal for another.
Codes may be used on questionnaires for value judgements. For example, you may be asked how you liked a certain chocolate bar and to allocate a number - 5 for Excellent, 4 for Good, 3 for Average, 2 for Unpleasant, 1 for Disgusting.
People may interpret the value 'Good' differently or may wish to give a value such as 'Average to Good'.
Extra comments are needed to make the data more useful but it is difficult to code 'It was too tough to chew and kept sticking to my teeth'
It may difficult to interpret the analysis of questionnaire responses where value judgements are used.
A code may not be understandable by a human.
Eg. a barcode 5031366014047....Codes may not be precise.
Eg. A code may be used on a survey for a person's nationality...E (English), W(Welsh), S(Scottish) etc.. but sometimes a person is Anglo-Welsh...
Extra codes would be needed...
Validation is the checking of data to make sure it is sensible data.
Value judgements can provide broad views of people but will be lacking in details.
EXAM TIP:
Encoding is not encryption.
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