4. Organisation And Structure Of Data

Question 1

Define key field

Answer 1

Unique item of data used to identify the individual record

Question 2

What is data verification

Answer 2

Used to check data has been copied correctly from original document

Question 3

What is data validation

Answer 3

Used to check data entered is sensible

Question 4

Examples of validation checks

Answer 4

☑️ range check
☑️ type check
☑️ length check
☑️ format check
☑️presence check
☑️lookup list
☑️check digit

Question 5

Examples of verification checks

Answer 5

☑️visual verification
☑️double data entry

Question 6

What is metadata

Answer 6

Information about the file stored along with it

Question 7

Metadata examples

Answer 7

Size of image
Image dimensions
Camera used
Image’s exposure

Question 8

2 common character sets

Answer 8

ASCII
Unicode

Question 9

Describe ASCII

Answer 9

Contains a limited number of characters but doesn’t use many bits

Question 10

Describe Unicode

Answer 10

Has more characters than ASCII but uses more memory

Question 11

Why are character sets used

Answer 11

Files can be sent between computers and understood and decoded

Question 12

Data type of a record

Answer 12

Can contain multiple data types

Question 13

Data type of an array

Answer 13

Contains only one data type

Question 14

Base10/denary numbers 0-16 in Hexadecimal

Answer 14

0-9 = same as base10
10 = A –> 15 = F 16 = 10

Question 15

Explain the concept of overflow

Answer 15

When bits disappear to the left and right in shift operations & addition, computers have special registers to note these overflows. Bits known as flags are set to remind the computer an overflow has occurred - keeps calculations accurate

Question 16

Bitmap graphics definition

Answer 16

Made up of pixels. Larger graphics = more pixels needed to maintain quality

Question 17

What happens when bitmaps are enlarged/scaled up

Answer 17

Quality is lost - known as pixelation

Question 18

Vector graphics definition

Answer 18

Consist of equations that describe relative distance of a point from a point of origin
Can be enlarged to any size without loss in quality
less storage space

Question 19

How does sampling sound work

Answer 19

Sample of amplitude at a specific time recorded as a binary number

Question 20

Greater samples per second (Hz) = ?

Answer 20

Better sound quality
More storage space

Question 21

Integer

Answer 21

Whole number positive or negative

Question 22

Boolean

Answer 22

One of two values e.g. True/False, Male/Female

Question 23

Real

Answer 23

Include rational and irrational numbers - fractions, integers and irrational numbers, positive and negative

Question 24

Character

Answer 24

a single character “f”

Question 25

String

Answer 25

A sequence of characters