S2 Flashcards
What is a population?
A collection of items/individuals
What is a census?
When information is obtained from all members of a population.
Give three advantages of a census.
- Every member is used.
- Unbiased
- Gives accurate answer
Give three disadvantages of a census.
- Long time to do
- Expensive
- Difficult to ensure whole population surveyed
What is a sample?
The chosen members of a population
What is a sampling frame?
A list of all of the sampling units.
Give three advantages of sampling
- Cheaper than census
- Destruction of all sampling units not needed (lifespan)
- Data easier to collect
Give a disadvantage of sampling.
Bias can occur
What is a random sample?
A sample in which every item has an equal chance of being selected
What is a sampling distribution?
All of the potential outcomes and their probability
What is a statistic?
A quantity calculated from the observations of a sample.
What is a critical region?
The range of values which lead to H0 being rejected.
What is the parametric form of an ellipse?
𝑥 = a cos θ , 𝑦 = b sin θ
What is the parametric form of a hyperbola?
𝑥 = a cosh θ , 𝑦 = b sinh θ
What is a hyperbola/ellipse?
A hyperbola/ellipse can be defined as the locus of a
point P which moves so that PS = e PN