Get ahead with a $300 test prep scholarship
| Enter to win by Tuesday 9/24
AP Stats 4.1-4.2 Quiz
Terms in this set (32)
the entire group of individuals that we want information about
attempts to contact every individual in the entire population
a part of the population we actually examine in order to gather information
involves studying a part in order to gain information about a whole
voluntary response sample
people who choose themselves by responding to a general appeal
the surveyor chooses the individuals easiest to reach
simple random sample
A sample of size n selected from the population in such a way that each possible sample of size n has an equal chance of being selected.
sample chosen by chance
what are two different types of probability samples
startified random sample, and cluster sample
stratified random sample
a sampling design in which the population is divided into several subpopulations called stratum, and random samples are then drawn from each one
a sample that consists of clusters that are more convenient to interview. The clusters should mirror the characteristics of the population. Everyone in the cluster is included in the sample
you observe individuals and measure variables of interest but you do not attempt to influence the responses
you deliberately impose some treatment on individuals to measure their responses
individuals on which the experiment is done
what the units are called when they are humans
specific experimental condition applied to the units
explanatory variables in an experiment
a variable not among the explanatory or response variables in a study but that may influence the response variable.
occurs when 2 variables are associated in such a way that their effects on a response variable cannot be distinguished from each other.
experimental units are assigned to treatments at random, suing some sort of chance process
the group of patients who receive a sham treatment. Can be given an active or inactive treatment.
when a control group is given an active treatment
What occurs when there are more experimental units?
there is less chance of a lurking variable
What are the three principles of experimental design
control, randomize and replicate
control the effects of lurking variables on the response, most simply by comparing two or more treatments
use impersonal chance to assigne experimental units to treatments. Balance the effect of lurking variables by creating roughly equivalent groups of experimental units
use enough experimental units in each group so that any differences in the effects of the treatments can be distinguished from chance differences between groups.
In order to conduct an effective experiment;
treat all experimental units identically in every way except for the actual treatments being compared
double blind experiment
neither the subjects themselves nor the people who have contact with them know which treatment any subject recieved
benefits of a double blind experiment
avoids unconscious bias
a group of subjects that are known before the experiment to be similar in some way that is expected to effect the response to the treatments.
a difference in the responses so large that it is unlikely to happen just because of chance variation