2.2 data and information
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2.2 data and information

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2.2 data and information 2.2 data and information Presentation Transcript

  • INFO 2
    Unit 2.2 Data and Information
  • Specification
  • What is Data?
    What types of data are there?
    What is a Bit
    What is a Byte
    What is a Kilobyte
    To consolidate you should be able to answer these questions…
  • 01001001011011100010000001110100011011110110010001100001011110011001001001110011001000000110110001100101011100110111001101101111011011100010000001110111011001010010000001100001011100100110010100100000011001110110111101101001011011100110011100100000011101000110111100100000011000110110111101101110011101000110100101101110011101010110010100100000011011000110010101100001011100100110111001101001011011100110011100100000011000010110001001101111011101010111010000100000011000100110100101101110011000010111001001111001
    01001111011000100110101001100101011000110111010001101001011101100110010101110011
  • In today’s lesson we are going to continue learning about binary
    Objectives
  • Data is raw facts and figures or a set of values, data has no meaning.
    Examination Results (DATA) : 3312, 2, 35, 3, 64, 4421, 2, 48, 3, 56
    Data is generated by an event e.g. Buying a product in a supermarket
    Loyalty card number
    Barcode number of each item bought
    Weight of apples
    Credit card number to pay for goods
    What is Data?
  • Data can arise in formats other than numbers and text
    Text (Alphanumeric)
    Number (Numeric)
    Boolean
    Audio
    Image
    Video
    Whatever the type of data bring input, computers store and process data using binary numbers.
    Types of data
  • What is data capture?
    Means the collection of data to enter into a computer
    How can we enter data into a computer?
    Keyboard
    Speech recognition
    Webcam
    Touch screen
    Scanner
    Bar code reader
    Sensors
    How data can arise
  • Direct Data Capture
    Collection of data for a particular purpose
    Direct Data Capture Methods
    Bar Code Reader
    MICR
    OMR
    OCR
    Sensors
    Direct and Indirect data capture
  • Indirect Data Capture
    Collection of data as a by-product from another purpose
    Example
    Using the data collected from reading barcodes at a super market till to work out stock levels
    Direct and Indirect data capture
  • GIGO
    In ICT GIGO stands for Garbage In Garbage Out
    It relates to Information only being as good as the data that is input
    i.e. I put incorrect data into a system (accidently or deliberately) then the information that is output will be incorrect.
    Use only a Pencil, one key colour and an A4 piece of paper to illustrate this Abbreviation and it’s meaning. Think about using a diagram, keywords and definitions to illustrate.
    Activity
  • Encoding is used by computers to convert the data into machine readable form i.e. binary
    Encoding Data
  • A single unit in binary is called a ‘bit’ (stands for binary digit)
    Computer memory is measured in ‘bytes’
    Onebyte is made up of eightbits
    One byte can store one character e.g. the letter A is represented by 010000001
    Binary Numbers
  • One byte can store one character e.g. the letter A is represented by 010000001
    Another variation of this byte can store another Character e.g. B is represented by 01000010
    A byte has 256 variations of data it can store
    Binary Numbers
  • Protocols have been developed to standardize the conversion of this binary code to content we are familiar with.
    ASCII is a standard that converts binary to character output
    MP3 is a standard that converts binary to audio output
    Protocols
  • Illustration
    Application
    Standard
    Output
    Device
    Standard
    Output
    M
    ASCII
    MP3
    Binary 1 bite
    01110010
    Application
    Standard
    Output
    Application
    Standard
    Output
    PSD
    WMV
  • The American Standard Code for Information Interchange
    Defines 128 characters (Requires only 7 bits of a byte)
    ASCII
  • We can work out the binary from the decimal and vice versa, the decimal from the binary
    ASCII
  • Binary to Decimal
    Simply plot the 1’s under the necessary values e.g. if I want 67
    ASCII
    C
  • ASCII
    Decimal to Binary is a little trickier
    Lets imagine you want to find the binary for decimal 116 (The letter t)
    You must work your way through the table below
    Can you take 128 from 116?NO (0)
    Can you take 64 from 116?YES (1) you now have 52
    Can you take 32 from 52?YES (1) you now have 20
    Can you take 16 from 20?YES (1) you now have 4
    Can you take 8 from 4?NO(0) you still have 4
    Can you take 4 from 4?YES(1) you now have 0
    Can you take 2 from 0?NO(0) you still have 0
    Can you take 1 from 0?NO(0) you still have 0
    0
    1
    1
    1
    0
    1
    0
    0
  • Use the two methods you have just learnt to convert the following:
    Binary to Decimal
    01001101 =
    10011111 =
    01100000 =
    00010100 =
    Decimal to Binary
    48 =
    239 =
    110 =
    17 =
    Activity
  • Use the two methods you have just learnt to convert the following:
    Binary to Decimal
    01001101 = 77
    10011111 = 159
    01100000 =96
    00010100 = 20
    Decimal to Binary
    48 = 00110000
    239 = 11101111
    110 = 01101110
    17 = 00010001
    Activity
  • Coding data is NOT the same as Encoding data
    Data is coded to reduce data entry and reduce the need for storage space.
    Imagine this scenario:
    You are conducting 500,000 questionnaires
    You ask each user to identify whether they are male or female
    The largest response would be ‘female’ which contains 6 bytes of data
    If all 500,000 users are female that means that the total storage for that one response will be:
    3000,000 bytes
    2929 Kilobytes
    2.8 Megabytes
    If you were to code this data by asking the user are you M/F
    The largest response would be M or F which both contain only one byte
    This would reduce the data storage to:
    500,000 bytes
    488 Kilobytes
    0.47 Megabytes
    Coding data
  • Examples of data that are coded are:
    Gender often asked as M or F
    Bank sort codes are a number (60-55-63) instead of the name of the branch
    Dates of Birth instead of 18th February 1981 it becomes 18/02/81
    Destinations at Airports DXB, LHR etc.
    Postcodes
    Codes are used because:
    Can be easier to remember (ISBN’s are not)
    Usually short and quicker to enter (thus fewer errors are likely to be made)
    Take up less storage space
    Ensure consistency
    Easier to check that the data is valid
    Who codes data and why?
    If the data is to become information it is likely that the data is decoded before it is output e.g. barcode (coded data) output information – total cost of product
  • Loss of precision
    Examples
    How old are you?
     12 – 15  16 – 18  19 – 23
    How would you rate this school?
     Poor  Good  Very Good
    (Value judgement is required here also)
    The colour of the article will be
    Problems with coding data
  • What is Processing?
    It is the work the computer does on the data to convert it into information e.g. searching, calculating, sorting etc.
    Processing
  • What is information?
    Information is data that has been processed, put into context and given a meaning. It must be understandable to the user.
    Information
  • Information is good quality if it is:
    Accurate
    Up-to-date
    Complete
    From a reliable source
    Relevant
    Quality of information
  • How accurate will depend upon its use:
    Bank statement details should be exact to the penny
    Whole School A Level pass rates at a school might be to the nearest 1% (This would be sufficient)
    Imagine inaccurate information relating to stock figures this could result in products not being available to customers or an over order resulting in to much stock to store.
    Thorough error checking and regular up dates must take place to ensure the information is as accurate as possible
    Accurate Information
    http://news.bbc.co.uk/2/hi/8176957.stm
  • Some information only has value within a specific time scale e.g. share prices.
    If information is out of date wrong decisions could be made. For example:
    An employee of a cinema taking a booking for the evening performance needs to know which seats are available at the time of booking not the ones available at the start of the day.
    Reports should contain dates and where possible times
    Keeping data up-to-date effects the costs
    Use to be batch processing now transaction processing
    Up-To-Date Information
  • If information is incomplete it loses its value and can misinform.
    If you collect details about a householder for insurance purposes and don’t request information about the value of the house, the house might be insured for the wrong value.
    If you conduct a survey and half of the questions are not answered your analysis of those results could be inaccurate.
    Complete Information
    http://www.bbc.co.uk/news/business-10701953
  • The internet offers a huge range of information. However, the internet is not governed, thus no one controls the content.
    Consider Wikipedia, it is an open source network that allows anyone who is registered to add content. There are editors who are able to check the validity but only to the extent of their knowledge base.
    Trusted sites like .gov .ae, BBC are recommended
    Information from a reliable source
  • Information is only valuable to someone who has use for it and its value will depend on its potential use.
    Relevant
    Obama’s views on the value of information, is it just a distraction?
    http://tek.io/hwJAiP
  • Global Positioning Systems (GPS)
    Are able to provide drivers with accurate, relevant and Up-to-Date Information
    GPS
  • How does social media impact the quality and value of information?
    Consider this Cairo activists comments:
    “We use Facebook to schedule the protests, Twitter to coordinate, and YouTube to tell the world."
    Discussion
    http://www.bbc.co.uk/news/world-africa-12289475
  • Past Paper Questions
  • Past Paper Questions
  • Past Paper Questions
  • Past Paper Questions
  • Past Paper Questions