statistics lol Flashcards
1
Q
median from a grouped frequency table
A
lower band+ number into category/ number in category x class width
2
Q
simple random sampling
A
- assign numbers to each sampling unit
- random number generator
- ignore repeated values
- match assigned numbers back to population member
3
Q
stratified sampling
A
- population divided into mutually exclusive strata, and random sample is taken from each
- number in stratum/ number in population x overall sample size
- higher quality sample
4
Q
simple random advantages and disadvantages
A
- free of bias
- easy, quick and cheap
- all = equal chance of selection
- sampling frame needed
- if population/ sample size = big, then ineffective
5
Q
stratified sampling advantages and disadvantages
A
- reflects population structure
- proportional representation of groups
- must be put into groups = long
- selection within groups, sampling frame = needed
6
Q
systematic sampling
A
- selected at regular intervals
- eg, every 10th sampling unit
7
Q
systematic sampling advantages and disadvantages
A
- simple and quick
- suitable for large samples/ populations
- sampling frame needed
- can have bias if sampling frame is not random
8
Q
random sampling methods
A
- simple random
- stratified
- sytematic
9
Q
non-random sampling methods
A
- quota
- opportunity
10
Q
quota sampling
A
-interviewer/ researcher selects sample that reflects characteristics of population
11
Q
opportunity sampling
A
- takes the sample from people who are available at the time that the sample is taken
- fit the criteria your looking for
12
Q
quota sampling advantages and disadvantages
A
- no sampling frame required
- quick, easy, cheap
- allows small sample to be representative
- can have bias
- dividing into groups = can be costly + inaccurate
13
Q
opportunity sampling advantages and disadvantages
A
-easy, quick & cheap
- unlikely to be representative
- highly dependent on the researcher
- can easily be biased
