A Level Maths – Statistics Exam
Questions And Complete Answers.
Population - Answer The whole set of items that are of interest
Census - Answer Observes or measures every member of a population
Sample - Answer A selection of observations taken from a subset of the population which is used to
find out information about the population as a whole
Census - Adv & Disadv - Answer Adv
- Completely accurate
Disadv
- Time consuming & expensive
- Cannot be used when the testing process destroys the item
- Hard to process large quantity of data
Sample - Adv & Disadv - Answer Adv
- Less time consuming & less expensive than a census
- Fewer people have to respond
- Less data to process than in a census
Disadv
- Data may not be as accurate
- May not be large enough to reflect about subsets in population
Sampling units - Answer Individual units of a population
, Sampling frame - Answer Sampling units of a population individually named or numbered to form a list
Simple random sampling - Answer One of every sample of size 'n' has an equal chance of being
selected
- requires a sampling frame
Systematic sampling - Answer The required elements are chosen at regular intervals from an ordered
list
- first element should be chosen at random
Stratified sampling - Answer The population is divided into mutually exclusive strata and a random
sample is taken from each
- proportion of each strata sampled should be the same
Stratified sampling formula - Answer The number sampled in a stratum = (number in stratum / number
in population) x overall sample size
Simple random sampling - Adv & Disadv - Answer Adv
- Free of bias
- Easy & cheap to implement for small populations and small samples
- Each sampling unit has a known and equal chance of selection
Disadv
- Not suitable when the population size or the sample size is large
- A sampling frame is needed
Systematic sampling - Adv & Disadv - Answer Adv
- Simple and quick to use
- Suitable for large samples and large populations
Questions And Complete Answers.
Population - Answer The whole set of items that are of interest
Census - Answer Observes or measures every member of a population
Sample - Answer A selection of observations taken from a subset of the population which is used to
find out information about the population as a whole
Census - Adv & Disadv - Answer Adv
- Completely accurate
Disadv
- Time consuming & expensive
- Cannot be used when the testing process destroys the item
- Hard to process large quantity of data
Sample - Adv & Disadv - Answer Adv
- Less time consuming & less expensive than a census
- Fewer people have to respond
- Less data to process than in a census
Disadv
- Data may not be as accurate
- May not be large enough to reflect about subsets in population
Sampling units - Answer Individual units of a population
, Sampling frame - Answer Sampling units of a population individually named or numbered to form a list
Simple random sampling - Answer One of every sample of size 'n' has an equal chance of being
selected
- requires a sampling frame
Systematic sampling - Answer The required elements are chosen at regular intervals from an ordered
list
- first element should be chosen at random
Stratified sampling - Answer The population is divided into mutually exclusive strata and a random
sample is taken from each
- proportion of each strata sampled should be the same
Stratified sampling formula - Answer The number sampled in a stratum = (number in stratum / number
in population) x overall sample size
Simple random sampling - Adv & Disadv - Answer Adv
- Free of bias
- Easy & cheap to implement for small populations and small samples
- Each sampling unit has a known and equal chance of selection
Disadv
- Not suitable when the population size or the sample size is large
- A sampling frame is needed
Systematic sampling - Adv & Disadv - Answer Adv
- Simple and quick to use
- Suitable for large samples and large populations
