ASCII Meaning-American Standard Code for Information Interchange
Explanation-A standard code made up of a set ofbinary digits & repersenting data
OMR Meaning-Optical Mark Recognition
Explanation-A scanner used to scan marks on a specifically designed document into the computer. OMR software changes the marks into meaningful data so that the computer can process it.
OCR Meaning-Optical Character Recognition
Explanation-A scanner is used to scan text on a document into the computer. OCR software on the computer changes the letters into characters that can be edited on a computer
Information & data
Data is raw facts & figures which have not been given a meaning, an example
43 67 56 89 45 77 90
Information is data that has been processed & given a meaning
John achieved 43% in his maths class
It can be processed by a computer system to produce information. It is input through an input device, then processed or changed in some way & the information is output to a screen or on paper. The data has now become information
Collecting data for processing
Dta must be colected on a form before being processed by a computer. A well-designed form will help ensure that the data collected is correct & complete. Information created from correct & complete data is more likely to be of hight quality. A form should include;
- A title suitabke for the pupose of the form
- A logo repersenting the company collecting data
- A prompt which represents each item of data being collected
- A suitable space to enter each item of data-eg tick box
- Instructions on how to fill out the form
- A brief explanation which clearly explains the purpose of the form.
When designing a form think about font, colour & positioning of items:
- The font chosen should be suitable for the intended audience
- The font should vary in size to emphasise section & headings
- The colour should be used to enhance the form where appropiate, eg to part into sections
- Images such as comany logos, should not onsucre areas of the form
Data checking- Verification
To ensure that the data has been entered correctly we use verification. The process involves comparing two versions of the data entered & detecting any differences, them correcting data where appropiate.
- Proofreading-Typed documents can be proofread to ensure hat they contain correct & accurate information.
- Double entry of data-The same data is keyed into the computer by two different computer operators. The computer system compares the two sets of data. Any mismatching data is rejected & muct be re-entered.
Data checking- Validation
Data collected using a data-entry screen must be checked, by the software, before it is accepted by the computer system. Checking data to ensure that it is acceptable & sensible is validation.
Validation of data ensures that the data is present, of the correct type, the the correct range & of the correct length.
- Presence-This will ensure that data has been entered into an area on the form. This check means that data which must be entered is not omitted.
- Length-This check will ensure that data entered is of the correct length
- Type-Used to ensure that the data entered is of the correct format, example is numeric
- Format-To ensure that the format entered is correct, eg ABC 123 not A1B2C3
- Range-To ensure that data entered is within a given range, eg pupil grades between A-E
- Lookup tables-To ensure that the data is within the allowable list.
Data checking-Check digit
This is a character which is added to the end of a code. The check digit is compared with the results of a calculation on the code. If the results of the calculation do not match the check digit, the code has to be input again. Eg the barcode on a book