Data is raw facts and figures before they have been processed. This means the raw facts and figures have no meaning.
Example: BAT56& OR 6783847BB
Identify some key facts about data.
- Data can be alphanumeric characters, sound or graphics
- Data is raw facts and figures
- data has no meaning
Describe what is meant by the term Information:
=Information is made by taking the data and processing it.
There is a formula for information:
Information = Data + Structure + Context + Meaning
Describe what is meant by these key terms: Data, S
- Data - the raw facts and figures
- Structure - how the data is presented
- Context - an environment where our prior knowledge and understanding can make sense of the data
- Meaning - data in the correct structure and placed in the right context
- Knowledge - the application of information to a situation.
Advantages and Disadvantages of using Text
- Clear to understand
- Lots of detail
- Need to be able to read
- Need to understand the language
- Can be confusing - level of language
- Lots of text cannot be read quickly
Advantages and Disadvantages of Graphics
- Multilingual - do not need language to understand an image
- can match what you see - physical shapes
- Can be confusing if you don't know the symbols
- some symbols dont mean the same thing in different countries
Advantages and Disadvantages of Sound
- No fixed position
- No line of sight required
- Good for visually impaired people
- No good in large ares - distortion of sound
- Usually language based
- May not know the sound - different alarms
- Need to be able to hear
Advantages and Disadvantages of Moving Pictures
- Lots of information conveyed
- Not language dependant
- Can exemplify text
- Problems if sound
Advantages and Disadvantages of LED
- Can allow data to be kept secure
- Can be used in noisy places
- Similar to graphics
- Need to be able to see the lights
- Combinations of lights may need to be known to be understood
Describe the data type: BOOLEAN
The boolean data type can only hold one of two values - True and false.
Describe the data type: REAL
This data type contains numbers which will have decimal places. It is used to hold numbers where precision is important.
Describe the data type: INTEGER
This data type contains whole numbers with NO decimal places. It is used where accuracy may not be of vital importance or the value allocated is specifically a whole number.
Describe the data type: TEXT/STRING
This is any alphanumeric character. This includes numbers, text and symbols. Text is used to convey basic information. Most importantly if you store anything as a string, no mathematical calculations are performed on it, i.e. Telephone Number
Describe the data type: DATE/TIME
This contains numbers and letters, which, depending on the format used, displays the date or time to different degrees of accuracy.
Describe Direct Data. Then identify the Advantages
Direct (Primary) data is collected from an original source. It is often physically collected by yourself.
- The source and collection methos is known and verified
- The exact data required can be collected
- Can change the data being collected in response to answers
- May not get a large range of data
- Data may not be available - Location/Time
Describe Indirect Data. Then Identify the Advantag
Data that has been used for a purpose that is different to that for which it was originally collected. Or the people or companies involved in collecting the data are different to those who use it.
- Large range of data available that could not have been collected directly
- Data available from different locations and time periods
- Analysis might already have been completed on some of the data.
- Do not know is any bias was placed on the collection
- Cannot be certain of accuracy of the recording of data
- May not have all the information on how, when and where it was collected to make a valued opinion on its usefulness
- If the information was not originally collected, may not be able to get hold of it
Describe what is meant by Accuracy
The data needs to be accurate. If it is not accurate you can not rely on the information it provides.
Describe what is meant by Relevance
The information must be relevant, if you have some information but it doesn't relate to the topic it is worthless. Having information that is not relevant can be a disadvantage, it increases the volume of data, which means longer is needed to look at it all.
Describe what is meant by Age
The information may be too old, information can change over time. If you know the information is from the past it may not be relevant now.
Describe what is meant by Completeness
If you only have part of the information then it is worthless. Data requires a context, structure and meaning for it to have value and to be useful.
Describe what is meant by Presentation
If information is presentated in a way that you can't understand or you can't find what you are looking for, it loses value. The presentation might be improved by sorting the data, or using a different method of representation.
Describe what is meant by Level of Detail
You can be given too much data, or too little. The volume of data determines whether you have enough to make a decision or too much. If you have too much it can be difficult to find what you require.
What is Encoding Data?
Encoding data is taking the original data and storing it in a different representation. What it stored is not the actual data but a representation of it.
.i.e. Blue Jeans Size 8 ---> BJ8
Monday - Mon
Advantages and Disadvantages of Encoding Data
- The precision of the data entered is coarsened - it makes the data less accurate.
- Limits 'choice' for example hair colour - Blonde .vs. Strawberry blonde
- It is impossible to set up a database to analyse every possible answer
- Need to know codes
- Encoding Judgements - everyone different
- Limit to number of codes
- Difficult to track errors
- Memory requirements are far less
- It's quicker to enter a code
- Codes can easily be tagged, so can be found in a database
- They have a precise structure
- is more secure
- Data can be validated
- Organises the data as it has a standard format
List and Describe Validation Methods
- Range Check - sets an upper and lower boundry for the data. The data entered must lie between these two values
- Type Check - this makes sure the data is the right type; integer, boolean, real, string, date...
- Presence Check - these make sure check that there is something entered (if needed) and will insist a value is inserted
- Length Check - ensures that the data cannot be more than the set number of characters
- Look Up Checks - it takes the value entered and compares it against a list of values in a seperate table, it can return a confirmation.
- Picture Checks - This is also known as a format check, it makes sure the combination of numbers and letters are in the right order. Because the mix of numbers and letters means that a type check cannot be applied.
- Check Digit - a check digit is calculated using a set of numbers and then aded to the end of them. If the check value is the same it will continue processing, if not a value needs to be re-entered.
Name and Describe the Verification Methods
- Double Entry - this means that the information is entered twice, and if the second piece doesnt match the first the computer will ask for it again twice. But this is not always good, as the person could enter the same, wrong piece of data.
- Manual Verification - is proof reading the data. It means visually comparing the source data and the typed data to spot any differences.
Describe Backing Up and Identify Back Up Devices
Backing up is making a copy of the original data incase of the original becoming corrupted by viruses or the files being deleted.
The back up is often kept else where, large companies often have large warehouses full of servers.
Back Up devices:
- Magnetic Tape
- Floppy Disk, Memory Card
- CD - RW
Describe the term Archiving
Archiving is for long term storage of data that is not required immediately. It is stored for future reference.
Describe Costs of Information:
- initial costs
- Upgrade and Repair
- Purchasing Licences - for desktop publishing, graphics software...
- Technical Support
- Training costs, so staff know how to use the software features
- Ink and Paper
- People working for the organisation
- The people needed to collect, collate, enter, process and output the data and information
- Software training costs
- Staff covering costs
- Expensive costs
Describe the following: Input, Processing, Storage
Input - this is taking information that is external to the system and entering it into the system. This may be manual input (keyboard) or automated input (OMR). Though it may also be input by electronic means (CD/Disk)
Processing - this is an action performed on the data. This includes sorting, searching and calculations on the data.
Storage - This is where the data is held. This may be the input data, or data held on the system that is required for processing.
Output - This is taking the information from the system and outputting it. The method may result in a printed output, output on screen or and electronic output.
Feedback - This is where the output from the system forms part of the input to the system, Feedback is usually applied to real-time situations.