Research Methods Chapter 6

Front 1

Sample from a population

Back 1

individuals of interest

Front 2

Inferential Statistics

Back 2

reach conclusions that extend beyond the immediate data alone. make inferences from our data to more general conditions.

Front 3

Census

Back 3

The whole population is researched
ex. All students in Geneseo

Front 4

Population

Back 4

Tangible: can be measured
ex. all students in Geneseo
Intangible: cannot be measured.
ex: PTSD is intangible b/c we don't know ALL people diagnosed.

Front 5

Probability sampling

Back 5

ex. 5,000 people w/ 50 samples; whats the probability you'll be selected - 1/100
Everyone has equal chance of being selected.

Front 6

types of probability sampling

Back 6

random sampling vs. random assignment.
Systematic: take every Kth person
Stratified: divide group of interest into strata and randomly select from each
ex. Boys vs Girls in Geneseo - randomly select 30 girls and 20 boys (Sample represents student pop.)
Cluster: when pop. list is not available (less common)

Front 7

Non-probability sampling

Back 7

impossible to specify the probability of selecting any 1 individual.
may or may not be representative.

Front 8

Types of non-probability sampling

Back 8

Multistage: choose clusters with specific characteristics and select from those individuals.
Convenience: selecting people who happen to be where you are at the time.
Quota: "targeting" people w/ certain requirements. Generally used for surveys and marketing.
Referral sampling: Participants refer others to your study; not random

Front 9

Diffusion of Information

Back 9

Future participants know too much about your study; referral sampling

Front 10

sample size depends on

Back 10

the power of the statistic
your research design (how many conditions)
size of the effect
variability of the data: low levels=very similar

Front 11

How to increase power

Back 11

increase # of participants