Data collection Flashcards

1
Q

Define a population

A

The whole set of data that is of interest

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2
Q

Define a Sample

A

The subset of the population intended to represent the population

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3
Q

Define a sampling unit

A

Each individual thing in the population that can be sampled.

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4
Q

Define a sampling frame

A

sampling units in a population being individually numbered to form a list.

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5
Q

what are the two types of sampling a population?

A

Census and Sample

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6
Q

define a sample

A

a subset of the population that is intended to represent the whole population

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7
Q

Define a census

A

An investigation of the whole population

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8
Q

what are the pros and cons of a census

A

Pros:
- gives a reliable and accurate result, representing the whole population

Cons:
- very time-consuming and expensive.
- a lot of data to process
- can’t be used for testing when the process destroys the item.

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9
Q

What are the pros and cons of a sample?

A

Pros:
- less costly and time-consuming
- More manageable bits of data.
- fewer people have to respond

Cons
- may not be representative of the whole sample
- sample size might not be large enough- so maybe not reliable
- might be less accurate.

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10
Q

what are the types of sampling methods

A
  • simple random
  • systematic
  • opportunity
  • quota
  • stratified
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11
Q

What is simple random sampling? how to carry it out?

A

It can be carried out through a sampling frame being assigned numbers, then using a random number generator or a calculator to choose. (ran# x range of sampling frame)

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12
Q

What is systematic sampling?

A

When a sample is chosen at particular intervals from a list.

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13
Q

What is stratified sampling?

A

when the population is divided into mutually exclusive strata, and is then randomly sampled from there.

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14
Q

What is quota sampling?

A

when a researcher selects sampling units that fit the characteristics of the whole population.

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15
Q

What is opportunity sampling?

A

When the people that are available at the time of the study, and fit the criteria for it are used as a sampling frame.

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16
Q

What are pros and cons of random sampling?

A

Pros:
- Not biased
- easy and cheap for small populations

Cons:
- a sampling frame is needed
- not suitable when the population size is too large.

17
Q

What are the pros and cons of systematic sampling?

A

Pros:
- simple and quick
- suitable for large populations

Cons:
- can introduce bias
- a sampling frame is needed

18
Q

What are pros and cons of stratified sampling?

A

Pros:
- sample accurately represents the population.
- guarantees proportional representation of the groups within a population.

Not usable if population too large
sampling frame needed

19
Q

What are the pros and cons of Quota sampling?

A

Pros:
- small sample can be representative of the population
- simple and easy, inexpensive

Cons:
- can introduce bias
- might have to split into more groups, which can add time and expense
- non-responses aren’t recorded

20
Q

What are the pros and cons of opportunity sampling?

A

Pros:
- easy
- inexpensive

Cons:
- dependant on the individual researcher
- Unlikely to provide a representative sample.

21
Q

What are the different types of data?

A
  • quantitative
  • qualitative
  • discrete or continuous
22
Q

What is continuous data?

A

A variable can take any value in a given range. eg: 2.5, 2.1 secs.

23
Q

What is discrete data?

A

A variable can take only specific values in a given range. Eg: you cant really have 4.5 people in a family.

24
Q

What are the places in the UK that have been mentioned in the large data set?

A

Heathrow
Camborne
Hurn
Leeming
Leuchars

25
What are the places internationally that have been mentioned in the large data set?
Jacksonville Beijing Perth
26
what are the assumptions of the particle model?
- mass concentrated at a single point - rotational forces and air resistance can be ignored
27
what are some assumptions of the rod model?
mass concentrated along a line no thickness rigid
28
what are the assumptions of the lamina model?
mass distributed as a flat surface
29
What are some assumptions about the uniform body model?
mass concentrated at the centre of mass.
30
What are some assumptions of the Light object model?
objects have 0 mass tension is the same at both ends of a light string
31
What are some assumptions of the inextensible string model?
acceleration is the same in objects connected by a taut inextensible string
32
What are some assumptions of the smooth surface model?
no friction
33
what are some assumptions of the rough surface model?
THere is friction present if acted on by a force
34
what is an assumption of a wire
treated as one dimensional
35
smooth and light pulley model assumptions
- pulley has no mass - tension on both sides is the same along the sides of the beam
36
What are some assumptions of the bead model?
Moves freely along a wire or string tension is the same on either side of the bead
37
what are some assumptions of the peg model
- dimensionless and fixed - can be rough or smooth (question dependant)