Research methods chapter 5-8 Flashcards
Research methods chapter 5-8
Mixed-access sampling
means that multiple methods are used to invite participants to a research study—phone (mobile or landline), email, addressed-based
mail, intercept, ads, etc.
Nominal Data
a type of qualitative data that categorizes items or variables into distinct groups without any inherent order or ranking
Ordinal Data
variables have natural, ordered categories and the distances between the categories are not known
Steps in Sampling Design
Define Target Population & Case
Define Population Parameters
Define & Evaluate Sample Frames
Define Number of Cases
Define Sampling Method
Define Selection & Recruiting Protocols
Interval
ordered data where the differences between values hold meaning, such as temperature or dates
Ratio
a form of quantitative (numeric) data. It measures variables on a continuous scale, with an equal distance between adjacent values
Sample Frame
a list of individuals, households, or institutions that can be sampled from a population
Problems with Sample Frame
Incomplete list
Out-of-date list
Too inclusive a list
Inappropriate List
The advantages of census over sample are more compelling when
The target population is
Small
High variability within the target population
Advantages of using a sample
Greater speed
availability elements
lower cost
greater accuracy
Validity of a sample depends on two considerations
accuracy and precision
Accuracy
the degree to which bias is absent from the sample
Precision
How accurate a sample is
What Is a Sufficiently Large Sample?
1,500 – 2,000 respondents
When to Use a Larger Sample?
The greater the dispersion or variance within the population, the larger the sample must be to provide estimation precision.
The greater the desired precision of the estimate, the larger the sample must be.
The narrower or smaller the error range, the larger the sample must be.
The higher the confidence level in the estimate, the larger the sample must be.
The greater the number of subgroups of interest within a sample, the greater the sample size must be, as each subgroup must meet minimum sample size requirements.
Nonprobability sampling
the probability of getting any particular sample may be calculated
Probability sampling
a controlled, randomized procedure that assures that each population element is given a known, nonzero chance of selection
simple random sampling
each population element has an equal chance of being selected into the samples. The sample is drawn using a random number table or generator.
systematic sampling
a probability sampling method where researchers select members of the population at a regular interval
Advantages and disadvantages of simple random sampling
Advantages
Easy to implement with random dialing
Disadvantages
Requires list of population elements.
Time consuming.
Larger sample needed.
Produces larger errors.
High cost.
Advantages and disadvantages of Systematic sampling
Advantages
Simple to design.
Easier than simple random.
Easy to determine sampling distribution of mean or proportion
Disadvantages
Periodicity within population may skew sample and results.
Trends in list may bias results.
Moderate cost.
Stratified sampling
Population divided into few subgroups.
Homogeneity within subgroups.
Heterogeneity between subgroups.
Random choice of cases from within each subgroup.
Cluster sampling
Population divided into many subgroups.
Heterogeneity within subgroups.
Homogeneity between subgroups.
Random choice of subgroups.
Qualitative research
Qualitative research is a type of research that aims to gather and analyse non-numerical data. interpretive research
Area sampling
a cluster sampling technique applied to a population with well-defined political or geographic boundaries. It is a low-cost and frequently used method
Nonprobability
uses subjective or non-random methods, such as the researcher’s judgment and experience
