1. Data and Information

2. Syllabus for 2.2

3. Lesson Objectives
All students will know the difference between data and information
Most students will be able to explain why there is a need to code data
Some students will be able to explain why data is encoded with examples

4. What is the difference between data and information?
5 minutes
What is the difference between data and information?
Students to pair and share their home learning from last week

5. Product information after scanning in the barcode
Data
Is raw facts and figures which have not been processed.
Product information after scanning in the barcode
What product information is shown on the screen after a barcode has been scanned?
Information
Is data processed by the computer into something with meaning.

6. There are FIVE forms of data, how many can you think of…2
minutes
There are FIVE forms of data, how many can you think of…
sound
text
numbers
DATA
Still images
Moving images

7. Automatic measurements or readings – CAN YOU THINK OF ANY EXAMPLES OF THIS?
Results from a questionnaire
From a transaction e.g. an order
How do we get data?
MIS – management information system, takes data and uses this to provide info that people can use to make a decision
From the output of another system e.g. MIS
From a survey

8. Data capture… Collection of data to enter into a computer
Can be entered in a variety of ways, depending on the source…
Keyboard
Speech recognition (using a microphone)
Webcam
Touch screen
Selection from list using a mouse
Sensors
Bar code reader
Transfer of pre-captured data from an external device (e.g. a digital camera)

9. Quality of the Data Source 1
GIGO (Garbage In Garbage Out)
If data input is poor the resulting information output will be poor i.e. corrupt, inaccurate etc.
Can you think of any “real life” examples?
Garbage In
Garbage Out

10. Examples of GIGO Examples of GIGO can include:
Unreliable questionnaires/surveys
e.g. inappropriate samples, badly worded questions etc.
Incorrectly calibrated instruments
e.g. an incorrectly calibrated balance will give incorrect measures of mass
Human error
e.g. transcription errors when entering data
Incomplete data sets
e.g. failing to account for “shrinkage” when measuring supermarket stock

11. Shortening data and assigning code – learn this definition for coding!
Coding data
Title
Forename
Middle Name
Surname
DOB
Sex
Year group
Mister
James
Dean
Arthur
22nd May 1994
Male
Year 12
Becomes…
Title
Forename
Middle Name
Surname
DOB
Sex
Year group Mr
James D.
Arthur
22/05/94 M 12
Shortening data and assigning code – learn this definition for coding!

12. Why bother to code data?
Easy to remember the data
Short – so quicker to enter the data and….
Less chance of making mistakes
More data can be seen on the screen – less scrolling
Takes up less storage space / compress data
Easier to check data being input is correct via validation/verification checks to ensure data is consistent and correct. Only applicable to limited ranges of data – why do you think this is?
Banks use sort codes to identify branches
Airports – LHR London Heathrow Airport
Can you think of any more??

13. Drawbacks to coding data
Precision of data can be lost (coarsened)
In the example all shades of blue are coded as “blue”
The user needs to know the codes used
How many of these top level domains do you know?
au, ch, de, ie, pk, fr, il, lk, es
Data in
Pink
Blue
Black
Blue
Stored data

14. Coding value judgements
Coding value judgements can be a particular problem as they are subject to personal opinion
What do you think of this presentation?
Good? Average? Poor?
One person’s good may be another person’s poor!!!
Value judgements are very difficult to encode without some coarsening (loss of detail)

15. Secret Language… ,

16. Write a one word message to your neighbour!
Secret Language…
Students to write and swap their messages
Write a one word message to your neighbour!

17. What is encoding and why does it exist?
Encoding is converting data into machine readable form for example binary code.
Exam tips
Ask you to compare coding & encoding using an example (usually 4 marks)
Just an encoding question – so explain what it means and give example (2 marks)
Just a coding question – these ones can be made up of 2,3, 4 mark questions. For example , why do we code (3 marks), example of coding? (1 mark), definition of coding (2 marks)

18. Encoding image files…
Meaning an image is represented in a certain way when it is stored. The way in which an image is encoded depends on how the image was produced. For example by digital camera / scanner / paint or drawing software etc.
Types of encoding used for an image:
Vector / Bitmap – what is the difference between these?
GIF – what is this ext normally used for?
JPEG – the most popular format for sharing images online
TIFF
WMF

19. Encoding sound files…
Sounds are not digital, so to save them on a computer requires data to be encoded. As sound files are quite large compression is used to reduce their file size during encoding.
Some popular sound file formats:
WAV – used with Windows, files are not highly compressed
MIDI – (Musical Instrument Digital Interface) used mainly to communicate between electronic keyboards, synthesisers and computers. These files are compressed to quite a small size
MP3 – uses compression to reduce the file size considerably, which is why is it the most popular format for listening to music on portable devices
SHOCKWAVE AUDIO – used for very high quality sound with a very small file size.