2. Probability: all quant
a. simple random, adv/diadv:
b. stratified random
c. multistage (cluster)
*This provides the highest level of sampling strategy
A. Simple Random
- *Simple random
- *Stratified random
- *Multistage (cluster)
: laborious, low risk of bias, representative of sample maximized
Advantages and Disadvantages
*No research bias.
*Generalizability to the larger population is maximized.
*Differences between the sample & population are purely chance.
*The larger the sample size the greater the representativeness or study external validity.
is that it is timely, costly & pose issues in obtaining accurate records/lists of every element of the population.
*Reader be warned: Every type of sampling has some drawbacks. Look for how the researcher addresses them in their report. Ask why the sampling type was chosen & if it is randomized is it random selection or random assignment.
- B. Stratified Random: time-consuming, low risk of bias, enhanced representative of sample
*The population is divided into homogenous strata or subgroups.
*The proportions of the sample represent the proportions noted of the concept being studied as it presents in the larger population.
*The aim is to get a representative sample.
*The concept is the same as nonprobability quota sampling but random selection of the larger population is used.
*It is difficult to find a population list containing complete information, it is time consuming, enrolling a proportion of the population is challenging & costly.
C. Multistage (cluster)
: less time-consuming than simple/stratified sampling, subject to more sampling errors than simple or stratified sampling, less representative than simple or stratified sampling
*This involves successive random sampling of clusters that progress from large to small until the sample criteria is met.
*Clinical nurse gerontological specialists are desired as a sample.
*1st sample: random sample of hospitals where CNS work (a list obtained from the CRNBC).
*2nd sample: CNS in each hospital from the 1st sample (a list from the HR department at each hospital). Random selection of 2 CNS from each hospital who meet the eligibility criteria set by the researcher.
D. Systematic Sampling
: more convenient & efficient than the other 3, bias in the form of nonrandomness can be inadvertently introduced, less representative if bias occurs as reult of coincidental nonrandomness
*A strategy where a subject is chosen at fixed intervals such as every 10th person (or 5th, 7th, 10th)