Summary Everything to memorise for statistics a level

Everything to memorise for statistics

Data collection

Census
measures every member of a population
Adv accurate result
disadv expensive testing may destroy sample


Sampling unit
Individuals of a population

Sampling frame
a list of sampling units


Random Sampling

Simple random sampling
Same chance of being selected use random number lottery
sampling
Adv bias free
disado need a sampling

systematic sampling
take every 4th unit K Itam
for starting point pick a random number between l and k
Adv quick to use
disadu need sampling frame


Stratified sampling
Sample represents groups Strata of a population
898 size of strata for each strata pick randomly
Adv reflects population
disadu pop must be classified in strata

, Non Random Sampling

Quota sampling
like stratified but strata filled by interviewer researcher
Adv no sampling frame
disadv non random potential bias


In nose available at the time
Adv easy cheap
disadu unlikely to be representative of whole population


Types of Data

qualitative
non numerical data


quantitative
numerical data
discrete specific values
continuous value
any

Large Data Set

UK stations
Cambourine
Horn from the
Heathrow botom of the Un
Leeming up
Leuchars v


Costal stations will be windy and wet
South stations are warmer and have more sunlight hours