Term
Key Terms: define
Homogenous 

Definition
all members of a population are/were identical in characteristics 


Term
Key Terms: define
Heterogeneous 

Definition
individual members of a population are different from each other in characteristics 


Term
Key Terms: define
Sampling 

Definition
the process of selecting observations (a sample) to provide an adequate description and robust inferences of the population. the sample is a representative of the population 


Term
Key Terms: define
Sample element 

Definition
A case or a single unit that is selected from a population and measured in some way  the basis of analysis 


Term
Key Terms: define
Universe with SIUE example 

Definition
The theoretical aggragation of all possible elements  unspecified to time and space.
ex. SIUE 


Term
Key Terms: define
Population with SIUE example 

Definition
The theoretical aggregation of specified elements as defined for a given survey defined by time and space.
ex. SIUE students 2014 


Term
Key Terms: define
Sample or target population with SIUE example 

Definition
The aggregation of the population from which the sample is actually drawn.
ex. SIUE summer students 2014 


Term
Key Terms: define
Sample frame with SIUE example 

Definition
A specific list that closely approximates all elements in the population  from this the researcher selects units to create the study sample.
ex. List of SIUE summer students 2014 


Term

Definition
A set of cases that is drawn from a larger pool and used to make generalizations about the population 


Term
Key Concepts
What does sample size depend on? 

Definition
 How much sampling error can be tolorrated
 Size of population
 varation within the population with respect to the characteristics of interest
 Smallest subgroup within the sample for which estimates were needed
 Sample needs to be big enough to properly estimate the smallest subgroup



Term
Key Concepts
What are the 4 different types of probability sampling? 

Definition
 Simple Random Sampling (SRS)
 Systematic random sampling (SS)
 Stratified sampling (StS)
 Cluster sampling



Term
Key Concepts
Explain Simple Random Sampling (SRS) with method and give example of how this is done 

Definition
 The basic sampling method which most others are based on.
 Method: a sample size 'n' is drawn from a population 'N' in such a way that every possible element in the population has the same chance of being selected
 ex. Random number table or drawing out of a hat



Term
Key Concepts
1.Explain Systematic Random Sampling (SS) method. 2.What does the sampling interval do?
3. why is SS better than SRS? 

Definition
 Starting from a random point on a sampling frame, every 'n'th element in the frame is selected at equal intervals.
 the sampling interval tells the researcher how to select elements from the frame (ex. 1 in 10, 3 in 60), this depends on sample size needed
 Emperically SS provides the same results but it is more efficent



Term
Key Concepts
Explain Stratified Sampling (StS) method. 

Definition
Divide the population by certain characteristics into homogeneous subgroups known as strata(s). A systematic sample is taken from each strata relative to the proportion of that stratum to each of the others. 


Term
Key Concepts
Cluster sampling
1. when would this type of sampling be used?
2. what do you trade for efficency? 

Definition
 when researchers lack a good sample frame for a dispersed/spread out population.
 accuracy


