OCR AS ICT G061 - All Chapters

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Chapter 1 – Data, Information, Knowledge and Processing

Data

Raw facts and figures, unprocessed, no meaning e.g. 3553vdvdb

Information

Taking data and processing it, based on certainties           Pe.g.

Information = Data (23042015), structure(23/04/2015), context (UK date), meaning (my birthday)

Representation Methods

Text

Adv: explanations, clear, read if noisy

Dis: language, long explanations, need to see

Pictures

Adv: no language, always there, ok if noisy

Dis: need to know signs, no explanations

LED

Adv: cheap, power efficient, little memory

Dis: meaningless, close to see them

Video

Adv: explanations, how to… videos

Dis: time consuming, hearing and visual, linear

Animation

Adv: convey actions, language dependant

Dis: only shows steps, no sound

Sound

Adv: grab attention, visual impairments, area

Dis: hearing, everybody hears, be there at time

Knowledge

Application of information to give understanding

Knowledge can change, add more information, based on rules

Knowledge base – what someone knows

Data Types

Boolean – one of two values e.g. Y/N, true/false, gender

Real – numbers with decimals e.g. 47.65, currency

Integer – whole numbers e.g. 54, number of people

String – alphanumeric characters e.g. hello, house number, telephone number

Date/Time – numbers and letters e.g. 07/06/2015, birthday

Static and Dynamic Data

Static doesn’t change, dynamic can change

Static

Dynamic

Limited information

Large volume of data

No internet access

Need internet access

More reliable

Not always reliable

Not updated quickly

Data updated quickly

Need the book/CD

Access anywhere

Data Sources

Direct data collected for purpose and by you e.g. mobile phone usage

Advantages

Disadvantages

Correct data

Costly to collect

Trusted source

Time to collect

Small sample size

Indirect data for different purpose, different org using data e.g. mobile phone info to catch criminals

Advantages

Disadvantages

Instantly available

Not meet requirements

Sources compared

Out of date

Large sample sizes

Unreliable

Not detailed

Quality of Information

Accuracy, relevance, age, completeness, presentation, level of detail

Encoding Data

Replacing data with shorter data e.g. January = Jan

Purpose – speed up processing, reduce storage, improve accuracy, improve presentation, security

Advantages – storage, processing speed, quick input, validation, presentation, confidentiality

Disadvantages – interpretation, accuracy, completeness, limited codes, value judgements

Validation

Purpose – ensure data is sensible, reasonable, in acceptable boundaries, complete

Process – data within boundaries, process during data input, reduce data entry errors

Range check – within a range e.g. date before today

Type check – data conforms to particular data type e.g. real

Length check – specific length e.g. 5 chars

Picture check – has a pattern e.g. XX99

Presence check – data exists e.g. cannot be NULL

Lookup check – data exists in a list e.g. M or F

Check digit – extra digit from calculation of original data

UPC check digit – ((odd numbers positions x 3) + even numbers positions) / 10 = 10 – remainder

ISBN check digit – the digit goes into the table, add results of multiply row, divide by 11, the remainder is subtracted from 11, if answer is 10 use X

Digit

0

2

0

1

3

5

3

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