ICT Unit 1: Topic 1

ICT Unit 1: Topic 1

1. Data and Quality of Data

   • Data, Information and Knowledge
     • Data- Raw facts and figures with no meaning. Data can be numbers, text, images or sound
     • Information- Data that has been processed by the computer.
       • Data+Meaning+Context=Information
     • Knowledge- Information that has had rules applied to it
   • GIGO
     • Stands for Garbage in Garbage Out
     • It means if you input rubbish data into the computer then you will get rubbish data out
   • Processing
     • Performing calculations or arranging the data into a meaningful order
   • Transaction
     • A piece of buisness
       • E.g. an order, purchase, or transfer of money

2. Encoding and Storing Data

   • Encoding
     • Assigning codes to the data to reduce it's size
     • E.g. S=Small, M=Medium, L=Large
     • E.g. LHR= London Heathrow, MAN= Manchester
   • Advantages
     • Takes up less storage space
     • Easily Transferable
     • Easier to back-up
   • Disadvantages
     • Easily stolen
     • Training is needed
     • Security problems

3. Data Validation

   • Errors that can be made
     • Transcription Error
       • Error made when typing in data using a document as the source of data
       • e.g. mishearing what a person says over the phone and entering it into the computer
     • Transposition Error
       • Error made when characters are swapped around so they are in the wronng order
       • e.g. writing tumlbr instead of tumblr
   • Validation Checks
     • Check Digit
       • A decimal number or alphanumeric character added to a number for the purpose of detecting the sorts of error humans normally make on data entry
       • e.g. Account numbers will have check digits to check that the numbers entered are correct
     • Range Check
       • checks that data inputted is within a certain range
       • e.g. when signing up for facebook you have to be 13 or older,so anyone with the birth year below 2000 would not be allowed to sign up
     • Presence Check
       • used to check that the correct data is entered into the correct fields
       • e.g. entering a username and password
     • Verification Checks are used to restrict the data that a user can enter to reduce errors

4. Data Verification

   • Pairty Check
     • used to make sure that the data sent is the same as the data that is received when data is transmitted from one computer to another
     • e.g sending an email from one person to another
   • Data verification checks that the data being entered into the system perfectly matches the source of data
     • e.g. checking text/data in an email and making sure when the other user receives it there are no errors