Chapter 5 Flashcards
We observe individuals and measure variables of interest but do not attempt to influence the response
Observational study
We deliberately impose some treatment on individuals in order to observe their response
Experiment
The entire group of individuals that we want information about
Population
Part of the population that we actually examine in order to gather information
Sample
Consists of people who choose themselves by responding to a general
appeal
Voluntary response
Choosing individuals who are easiest to reach
Convenience sampling
The sampling method is ____ if it systemically favors certain outcomes
Biased
Every set of individuals has an equal chance to be the sample actually selected
Simple random sample (SRS)
The use of chance to divide experimental units into groups
Randomization
Divides the population into groups or clusters. Some of these clusters are randomly selected. Then all individuals in the chosen clusters are selected to be in the sample
Cluster sampling
What is the difference between a stratified sample and a cluster sample
A stratified sample we study a random sample of individuals in every sample and in cluster sampling we study all the individuals in the chosen clusters and none of the individuals in other clusters
Occurs when some groups of the population are left out of the process of choosing the sample
Under coverage
Occurs when an individual chosen for the sample can’t be contacted or does not cooperate
Non response
Caused by the behavior of the interviewer or the respondent or from misleading due to poorly worded questions
Response bias
Confusing or leading questions that effect the reposen of the survey takers
Poorly worded questions
The individual on which the experiment is done
Experimental units
A specific experimental condition applied to the units
Treatment
The explanatory variables in an experiment
Factors
Controls the effects of the the lurking variables on the response, most simply by comparing two or more treatments
Control group
Conducting the experiment on many units to reduce chance variation in the result
Replication
Used impersonal chance to assign experimental units to the treatments
Randomization
When an observed effect is so large that it would rarely occur by chance
Statistical significance
A group of experimental units or subjects that are known before the experiment to be similar in some way that is expected to affect the response to the treatment
Block designs
Compares just two treatments that are matched as closely as possible
Matched pair design
