Sampling ; Large Data Set Flashcards
What is a population
Population is any set of things we want to study
What is a census
A census is when we want to collect data of every member or thing in a population
What is a sample
Any subset of a population
What are inferences
Inferences is when you use data from a sample to make estimates
What is opportunity sampling and give a +ve and -ve
Opportunity sampling means choosing respondents based on their availability and convenience
+ve cheap and convenient
-ve may not be generalisable
What is simple random sampling and give a +ve and -ve
In simple random sampling every possible sample has an equal chance of being selected
+ve produces an unbiased sample
-ve hard to doin practice
What is systematic sampling and give a +ve and -ve
Systematic sampling means taking participants at regular intervals from a list of the population
+ve avoids unwanted clustering of data
-ve requires a list of the entire population
What is stratified sampling and give a +ve and -ve
Stratified sampling means splitting the population into groups based on factors relevant to research, then opportunity sampling from there
+ve Produces a sample representative over the factors identified
-ve time consuming and expensive
What is quota sampling and give a +ve and -ve
Quota sampling means splitting the population into groups based on factors relevant to the research then opportunity sampling from there
+ve ensures the sample is representative over the factors identified
-ve may not be generalisable
What is cluster sampling and give a +ve and -ve
Cluster sampling means splitting the population into groups based on convenience
+ve cheap and easier than other random methods
-ve less accurate than other random methods
What are the pros and cons of a census
Pro: data for every member of the population
Con: time consuming and expensive and may be destructive
What are the nine body types in the lds
1,2,3,4,5,6,13,14,96
Where is the data in the lds from
London
South west
North west
What is the engine size measured in
Cm^3
How many cars in the lds
92
Explain the emission rate of Carbon dioxide
Carbon dioxide emissions are recorded for 83% of cars
For most cars this means 173g/km is used per km of travel
What percentage of cars are diesel
In the department of transport the original data set, 24% of cars are diesel
This means they likely have particulate data for 24% of cars
What are the propulsion types
1 petrol
2 diesel
3 electric
Combined fuel types:
7 gas/petrol
8 electric/petrol
What does gas/petrol refer to
Gas petrol refers to a car which takes petrol but can also take liquid petroleum gas
How do code 1 and 7 differ
There is only one car in the LDS with propulsion type 7
What does electric/petrol refer to
Electric/petrol refers to a car which takes petrol but also runs partly on electricity
All of the cars with this propulsion type were registered in 2016
