Stratified sampling (AQA GCSE Statistics): Flashcards
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Practise the cards
10 cards from this deck
What is a stratum in statistics?
What is a stratum in statistics?
A distinct group in a population sharing common traits.
How do you ensure proportional representation in sampling?
How do you ensure proportional representation in sampling?
Sample must reflect the same proportions as the population.
How many males in a sample of 40 from 120 males in 200?
How many males in a sample of 40 from 120 males in 200?
24 males (0.6 x 40 = 24) and 16 females.
How to calculate sample size in stratified sampling?
How to calculate sample size in stratified sampling?
Sample size = (stratum size/total population) x total sample.
How many from Class A (34) in a sample of 20 from 80?
How many from Class A (34) in a sample of 20 from 80?
9 children (34/80 x 20 = 8.5, rounded).
What to do if rounding causes total to differ?
What to do if rounding causes total to differ?
Adjust by reducing the largest stratum by one.
What is a sampling frame?
What is a sampling frame?
A list of population members with relevant characteristics.
Why is stratified sampling more reliable?
Why is stratified sampling more reliable?
It ensures all important groups are represented.
Calculate sample size for Class B (28) in 20 from 80.
Calculate sample size for Class B (28) in 20 from 80.
7 children (28/80 x 20 = 7).
What is the advantage of stratified sampling?
What is the advantage of stratified sampling?
Produces more accurate results than simple random sampling.