Data Representation and validation Flashcards
What are the 2 factors effecting the file size of an image?
- Colour depth
- Image Resolution (The amount of pixels in an image)
What is the colour depth and how do you work out the amount of colours possible?
The amount of bits in a pixel which represents a colour. The more bits there are, the more colours can be displayed
2^bitDepth= possible colours
- 4 bit colour depth 16 colours (2^4)
-8 bit colour depth = 256 (2^8)
How do you work out the file size of an image?
Resolution (pixels on X axis × pixels on Y axis) x colour depth = file size
How is image data stored?
They are stored in files where binary data is placed into a bit map.
Why do some image files have more bytes than expected?
Metadata such as:
- Data when photo was taken
- Name of file
- Location of take image
- details of the image
What is the difference between analogue and digital sound waves?
Analog- Continuous and ‘smooth’
Digital- Discrete and a measurement of analogy waves
What are the audio converters?
ADC - Analog-to-Digital Converter
DAC- Digital-to-Analog Converter.
What the 3 factors affecting the file size of an audio file?
- Sample resolution (Audio Bit depth)
- Sample rate (Amount of analogue readings taken per second- 1hz = 1 sample per second)
- Seconds of audio
How do you calculate audio file size?
Audio bit depth (bits) x Hertz (Hz) x seconds = File Size (bytes)
What are the data types (6) and examples?
Integers (1,2,3,4..)
Characters (A,#,8,@)
String ("Hello World")
Real (3.141)
Date (21/05/2022)
Boolean (True/False)What is the difference between Validation and Verification?
Validation- When code is used to check that data entered into a system is reasonable, sensible and legal (If it’s valid)
Verification- When users the check the data in the system to check it perfectly matches the source of data (E.g. Questionnaire results)
What are the 5 validation checks?
Type - (Checks data type)
Format - (Checks pattern)
Length - (Checks length/ number of character required)
Presence - (Checks Entered and not blank)
Range - (Checks Upper and low boundaries)
What are the 3 Verification checks?
- Proof Reading
- Double entry of data (Check if they are the same)
- Sending back printouts
What does a type check do?
Checks the right type of data is being entered
What does a format check do?
Checks the data being entered is the right pattern (e.g. Postcode = LLNN NLL)
What does a length check length do?
Checks the data being entered is the right length or number of characters required (Not too little or too many)
What does a presence check do?
Checks data has been entered and not left blank
What does a range check do?
Checks boundaries to make sure data falls between an upper and lower value.
(E.g. Month of the data of birth must fall between 1 and 12)
What are the two characteristics of data structures?
- Static/ dynamic (Scalability)
- Mutable/ immutable (Editability)
What is the difference between a static and dynamic data structures?
Static- When a data structure is of a fixed size (E.g. An array)
Dynamic- When a data structure can grow and shrink (E.g. Lists)
What is the difference between a mutable and immutable data structure?
Mutable- Allows a structure to be edited (E.g. An Array)
Immutable- A structure where data can out be changed, only added. (E.g. String)
What is the correct name for a word document?
A Word Processor (package)
What is the correct name for a excel?
A Spreadsheet
What is the correct name for photoshop/ paint?
Image manipulator
