Data Representation and validation Flashcards

1
Q

What are the 2 factors effecting the file size of an image?

A
  • Colour depth

- Image Resolution (The amount of pixels in an image)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the colour depth and how do you work out the amount of colours possible?

A

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 well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How do you work out the file size of an image?

A

Resolution (pixels on X axis × pixels on Y axis) x colour depth = file size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How is image data stored?

A

They are stored in files where binary data is placed into a bit map.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why do some image files have more bytes than expected?

A

Metadata such as:

  • Data when photo was taken
  • Name of file
  • Location of take image
  • details of the image
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the difference between analogue and digital sound waves?

A

Analog- Continuous and ‘smooth’

Digital- Discrete and a measurement of analogy waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the audio converters?

A

ADC - Analog-to-Digital Converter

DAC- Digital-to-Analog Converter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What the 3 factors affecting the file size of an audio file?

A
  • Sample resolution (Audio Bit depth)
  • Sample rate (Amount of analogue readings taken per second- 1hz = 1 sample per second)
  • Seconds of audio
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do you calculate audio file size?

A

Audio bit depth (bits) x Hertz (Hz) x seconds = File Size (bytes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the data types (6) and examples?

A
Integers (1,2,3,4..)
Characters (A,#,8,@)
String  ("Hello World")
Real (3.141)
Date (21/05/2022)
Boolean (True/False)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the difference between Validation and Verification?

A

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)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 5 validation checks?

A

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)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the 3 Verification checks?

A
  • Proof Reading
  • Double entry of data (Check if they are the same)
  • Sending back printouts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does a type check do?

A

Checks the right type of data is being entered

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does a format check do?

A

Checks the data being entered is the right pattern (e.g. Postcode = LLNN NLL)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does a length check length do?

A

Checks the data being entered is the right length or number of characters required (Not too little or too many)

17
Q

What does a presence check do?

A

Checks data has been entered and not left blank

18
Q

What does a range check do?

A

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)

19
Q

What are the two characteristics of data structures?

A
  • Static/ dynamic (Scalability)

- Mutable/ immutable (Editability)

20
Q

What is the difference between a static and dynamic data structures?

A

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)

21
Q

What is the difference between a mutable and immutable data structure?

A

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)

22
Q

What is the correct name for a word document?

A

A Word Processor (package)

23
Q

What is the correct name for a excel?

A

A Spreadsheet

24
Q

What is the correct name for photoshop/ paint?

A

Image manipulator

25
What is the correct name for a PowerPoint?
Presentation software
26
What are the two types of compression?
Lossy and Lossless
27
What happens in Lossless compression?
It finds groups of repeating data and records the data along with the number of times it was repeated
28
What happens in lossy compression?
Removes some of the data and reconstructs it in a way to try and hide the lost data usually by averages. Data loss is irreversible.
29
What are the files types that use Lossy compression?
JPG GIF MP3
30
What are the files types that use Lossless compression?
PNG | TIF
31
What asci number does the capital letters start and the lower case letters?
Capitals- 65 | Lower case- 97
32
How are images stored on a file?
Each coloured pixels position and colour can be stored in a bitmap. In a black and while image, a single bit can be used per pixel with 0 representing black and 1 white. For RGB images, the bit depth can be increased and more bits used to represent each colour in the image.
33
How is sound stored on a file?
- Sound is sampled by converting analogues sound waves into digital waves that can be stored in a file. - The frequency (Hz) of the samples can be increased as well as the amplitude (bit depth) of each sample to improve the quality of the sound. - Different amplitudes can correspond different bit values per reading
34
How is a string stored on a file?
Each character is converted into a binary number before being stored on the computer system which each correspond to it's ascii character.