Sampling
A sample selected from a population in such a way that every individual has an equal chance of being chosen
What is a simple random sample?
This introduces bias into a study by using an easily available group to form a sample.
What is convenience sampling?
This is measured as part of an experiment but is not controlled by the experimenter.
What is a response variable?
The smallest entity to which a treatment is applied.
What is the experimental unit?
A method in which the population is first divided into homogenous groups called strata that differ from the rest of the population. A simple random sample is then taken from each strata and grouped together to make the final sample.
What is a stratified random sample?
This introduces bias into a study by allowing individuals to volunteer to be in the sample.
What is voluntary response sampling?
In a study comparing three popular diets, experimenters realized too late that they would not be able to distinguish between their intended reponse variable and this.
What is a confounding variable?
The procedure used in an experimental design to eliminate the effect of some variable on the response.
What is control?
Nonoverlapping subgroups of a population. Each subgroup resembles the entire population.
What is a cluster?
This occurs when the method of observation or asking questions tends to produce values that systematically differ trom the true value in some way.
What is response bias?
In the relationship between lung cancer and smoking, lung cancer is said to be this.
What is a response variable?
A procedure that creates groups of experimental units (called blocks) that are similar with respect to one or more potentially confounding variables.
What is blocking?
Sampling in which an individual or object, once selected, is put back into the population before the next selection.
What is sampling with replacement?
This occurs when the way a sample is selected systematically excludes some part of the population of interest.
What is selection bias?
This is the variable that is controlled by the experimenter.
What is the explanatory variable?
This ensures that an experiment does not favor one experimental condition over any other and tries to create "equivalent" experimental groups.
What is random assignment?
A method that selects from an ordered arrangement of a population by choosing a starting point at random from the first k individuals and then selecting every kth individual after that.
What is systematic sampling?
This occurs when responses are not obtained from all individuals selected into the sample.
What is nonresponse bias?
In a study of climate change, fuel emissions from vehicles are referred to as this.
What is the explanatory variable?
The design strategy of using the largest sample size possible in order to create multiple observations for each treatment.
What is replication?