Rangkuman Tekhnik Sampling

Sample adalah subset dari populassi

Get information about large populasi

-          Less costs

-          Less field time

-          More accuracy i.e. can do a better job of data collection

-          When its imposible

Target population

The population to be studied/ to which the investigator wants to generalize his result

-          Sampling unit

Sampling unit from which sample can be selected

-          Sampling frame

List of all the sampling units from which sample is drawn

-          Sampling scheme

Method of selecting sampling unit from sampling frame

Types of sampling:

1.       Non probability sample: tidak dapat membuat kesimpulan. Probability of being chosen is unknown cheaper-but unable to generalize potential for bias

-          Convenience samples (ease of access)

Smple is selected from elements of a population that are easily accessible

-          Snowball sampling (friend of friend……etc)

-          Purposive sampling (judgemental)

You chose who you think should be in the study

-          Quota sample

2.       Probability samples

-          Random sampling

Each subject has a known probability of being selected

-          Allows application of statistical sampling theory to result to

Generalize

Testhypotheses

Conclusions

-          Probability samples are the best

-          Ensure

Methods use in probability samples:

-          Simple random sampling (memilih secara acak)

-          Systematic sampling : sampling fraction (ratio between sample size and population size)

-          Cluster sampling: cluster a group of sampling units close to each other i.e crowding together in the same area or neighborhood

-          Stratified sampling: melihat stratanya

-          Multi stage sampling

Errors in sample

-          Systematic eror (or bias)

Inaccurate response (information bias) selection bias

-          Sampling eror(random error)