Data, information and knowledge Flashcards
Need to look at leaflet of past paper questions- lots of diagram q's
What is:
i) Data
ii) Information
iii) Knowledge
i) Unprocessed raw facts and figures without context
ii) Processed data with context
iii) Applied information to make decisions
Explain how a check digit is calculated
« Each digit is multiplied by a weighting based on its position
« The products are calculated
« The total is divided by 11 and the remainder obtained
« The check digit is 11 minus the remainder
Explain how a check digit will detect a transposition error
If two digits are interchanged the weightings will change
Identify 6 factors of quality of information
Up-to-date Complete Reliable Relevant Accurate Presented effectively
Identify two methods of data verification
Double entry
Proofreading
Apart from a check digit name and describe three types of data validation
«Length Check- no. of characters must be correct
«Presence Check- field value is required
«Type Check- data must be correct type, eg string
«Range Check- Value must lie between two units
«Format Check- characters must match pre set pattern
«Lookup Table- value must already exist in table
What is lookup table data validation
The value must already exist in a table or drop down list
Explain how verification can be used to detect errors
Proof Reading- The person inputting data compares data entered to the source data ensuring they are the same or identical
Double Entry- The data is entered twice and the system then checks that both versions match.
Show that 13217 is a invalid product code.
Check digit should be 11-8, i.e 3. Not 7
What is the purpose of data verification
To check that data input is as intended and matches source data.
Describe how data verification can detect errors
The person keying in data performs visual check on what has been entered, can be asked to confirm the details
Explain the purpose of data validation.
To enable the computer to ensure that data is meaningful/reasonable/complete/sensible NOT TO ENSURE ITS CORRECT
Describe four factors which may effect quality of information
Up-to-date: Information will not reflect current situation, some data may change. Eg Address
Relevant: Info may not include all essential details or may include unnecessary and irrelevant info.
Complete: Information may omit essential detail eg some fields may not be complete
Accurate: Info may be inaccurate eg invalid information in a field due to entry error
Presentation: It may not be appropriate for intended info, eg. lack of annotation, inappropriate format
Discuss the impact of poor quality information on a supermarket checkout
If data is wrong then supermarket might order wrongly, if stocks are low product may not get re-ordered on time in info is not up-to-date, if data is not presented effectively the supermarket may lose customers, if info inaccurate a customer may be charged the incorrect amount
Discuss validation that may be applied at a supermarket checkout
Validation check on check digit on product which will be scanned, and the computer will calculate check digit and will compare it to check digit on product, weighting and modulus 11 will be used.
