- Created by: milly
- Created on: 04-01-13 15:03
What can Data be?
Data can be numbers, words, images, sound and video
Deffintion of Data
Data consists of raw facts and figures (e.g. readings from sensors, survey facts, etc.)
These raw facts and figures are meaningless because they lack relevance.
If you look at data it is either no use to you or not in a form that you can use.
What is Inforamtion?
Information is data that has been processed in some way to give it meaning and context.
What does Inforamtion that is prcoessed mean?
Processed can mean:
· Having calculations performed on it
· Converted to give it meaning
· Organised in some way (putting it into numerical order, alphabetical order, into a database structure, etc.)
What is knowledge?
Knowledge is obtained from information by applying rules to it
Example of Knowledge
· Here is a number: 39
· This is data because there is no meaning.
· If this is a child’s temperature in Celsius, this is information. If we apply the knowledge that normal body temperate in 37 ۫ we now know that the child should see a doctor.
GIGO (garbage in garbage out
“if you enter incorrect data into the computer then the output form the computer will also be incorrect.”
Ways Data Can Arise
- From transaction (e.g. buying a download over the internet.)
- From the results of an experiment
- From automatic measurements using sensors (e.g. temperature rainfall, pressure, etc.)
- From a survey (e.g. to find the most popular crisp flavour in the class)
Why do we encode Data?
- Coded data is quicker to type
- It takes up less storage space on a disk.
- It is easier to do a validation check
- Faster to access data that is coded
- It is quick to sent data over a network.
Examples of coding:
- M and F
- GB, D, IR
- S, M, L , XL
- LHR, GTW, MAN, LPL
Advantages using ICT for Storing Data
- Less storage space is needed
- Data is easily copied
- Easier to backup
- Easily transferred onto networks
- Fast access to stored data
- Data can be put into a secret code when stored (encrypted)
Disadvantages of using ICT for Storing Data
- Copying data, means copyright holders lose out on money when music’ games and videos are copied
- Data can be copied quickly, means personal data can be stolen
- Reliance on networks
- Training needed
- Security problems
Whats Data Validation?
Validation is a check performed by a computer program during data entry. It ensures the data is sensible and reasonable.
Types of validation checks
- Validation checks are used to restrict the user as to the date they can enter. There are many different validation checks each with their own special use.
- Data type checks- check that the data type being entered is the same data type as that entered for that filed.
- Presence checks- to check that a field has been entered
- Range checks- are preformed on numbers to check that a number being entered is with a certain range.
- Format checks- to make sure they meet set criteria i.e. a post code must be in the form of 2 letters, followed by 2 numbers. Followed by 2 letter i.e. JE3 1JT.
Whats Data Verification?
Verification- means checking that the data being entered in to the ICT system perfectly matches the source of the data. For Example if details from an order form were being typed in using a keyboard, the when the user was finished, the data on the screen should be identical to that on the paper form (the data source.) (By a human)
Methods of Verification
- Visual check/proof reading- this involves one user carefully reading what they have typed in and comparing it with what is on the data source (order forms, application form etc.) for any errors which requite correcting)
- Double Entry of Data- using the same data sources to enter the details into the ICT system twice and only h=when the two sets of data are identical will they be accepted for processing.
- Parity Checking- involves checking data after it has been sent through a wire or wirelessly. These check that the data has not been corrupted in any way.
How errors can occur
- Errors in data can occur during:
- Transcriptions i.e. mishearing words.
- Input i.e. mistyping words
- Processing i.e. mistakes in formulas
- Transmission i.e. data getting corrupted as it travels through wires.