Shared Flashcard Set

Details

Stat 1200
N/A
54
Mathematics
Not Applicable
02/21/2010

Additional Mathematics Flashcards

 


 

Cards

Term
Population
Definition
collection of all units of potential interest
Term
Sample
Definition
collection of units upon which we actually take measurements
Term
Survey
Definition
Ask people questions and record their answers.
Term
Random experiment
Definition
assigning people randomly to one of two groups
Term
Random assignments
Definition
Ex. giving one group an active drug and other group a placebo
Term
Observational Study
Definition
Observing your sample
Term
7 components of a good study
Definition
SOURCE, RESEARCHERS, INDIVIDUALS OR OBJECTS STUDIED, MEASUREMENTS,SETTING, EXTRANEOUS DIFFERENCES, MAGNITUDE.
Term
categorical variables
Definition
(aka qualitative variables) those that divide subjects into groups, BUT dont allow mathematical operations to be performed.
Term
Measurement variables
Definition
(aka quantitative variables)those for which the responses are meaningful numeric values.
Term
nominal variables
Definition
categorical variables that have no nature order (ex. eye color, home state, ethnicity)
Term
Ordinal variables
Definition
Categorical variables that HAVE a natural order. (ex. Fresh, Soph., Junior, Senior and Likert Scale- strongly agree, somewhat agree, etc.)
Term
Interval variables
Definition
Measurement variables for which differences are consistent but ratios are not. Ex. Temperature
Term
Ratio variables
Definition
Measurement variables for which ratios are consistent. Ex. age, height, distance, # of chairs in a room
Term
Discrete variable
Definition
measurement variable that you can actually count the # of possible responses. Ex. number of automobiles that wrecked on a freeway, 0,1,2,3 you cant have 2.8 or 3.6. YOU CAN COUNT THE AMOUNT WITHOUT HAVING TO ROUND THE NUMBER OFF
Term
Continuous variable
Definition
measurement variable that can be anything within a given interval. Ex. Age
Term
Bias
Definition
a systematic prejudice in one direction, survey questions may be worded in such a way that the responses are biased.
Term
Variability
Definition
discrepancies (vary from one to the next) between repeated measurements, Ex. measuring the length of a table with a ruler
Term
Natural variability
Definition
Variability that cannot be explained or predicted, Ex. unemployment.
Term
Valid measurement
Definition
measures what it claims to measure
Term
Reliable measurement
Definition
gives approximately the same result when repeated on the subject, Ex. bathroom scale
Term
Confidential
Definition
respondents identities are known but protected, these surveys allow a follow up
Term
Anonymous
Definition
respondents' identities are unknown, these surveys dont allow a follow up
Term
Open question
Definition
essay, short answer.
Term
closed question
Definition
multiple choice
Term
What do you want from a sample?
Definition
-Representative and small as possible, but still reliable
Term
Unit
Definition
single individual or object
Term
Frame
Definition
a list of units from which the sample is chosen
Term
Census
Definition
a survey in which the entire population is measured
Term
Simple Random Sample
Requirements for selection?
Definition
a sample collected in such a way that every conceivable group of units of the correct size has an equal chance of being the one selected. Requirements - a frame, a random # generator.
Term
Sampling error
Definition
random chance
Term
Sampling error
Definition
random chance
Term
Nonsampling error
Definition
poor methods
Term
Margin of error is a measure of what?
Definition
sampling error
Term
Stratified Random Sample
What are some advantages of this sampling?
Definition
Procedure: divide the population into groups (strata) and then collect a simple random sample from each group.
-The advantages have info on each strata available and its less expensive to conduct.
Term
Cluster sample
Definition
Procedure: divide the population into groups (clusters). Take a simple random sample of clusters and measure all units within the selected clusters."every subject from some groups"
Term
Systematic sampling
Definition
select units from the frame according to some pattern, perhaps every 10th person.
Ex. select the first person in each row from a lecture hall.
Term
Multi stage sampling
Definition
a sampling plan that combines 2 or more sampling procedures.
Term
Sampling disasters
Definition
1) getting a volunteer sample, no pretense of randomization
2)Using a convenience or haphazard sample - use whoever is standing around
Term
Sampling disasters
Definition
1) getting a volunteer sample, no pretense of randomization
2)Using a convenience or haphazard sample - use whoever is standing around
Term
Difficulties for sampling
Definition
1)using the wrong frame, 2)not reaching the individuals selected, 3)non-response(volunteer response)
Term
Response variable (RESP)
Definition
the RESP is the primary measurement of interest. Usually a study considers only one RESP.
Term
Explanatory variables (EXPL) or factors
Definition
an EXPL is other info about each subject that may explain why the subjects differ in respect to the RESP, studies often have many EXPL
Term
Typical situation
Definition
compare 2 or more groups based on the RESP. The group is the EXPL.
Term
Experiment
Definition
a study which the EXPL is controlled (manipulated) by the researcher. EXPL is a treatment.
Term
Observation studies
Definition
a study in which the value of EXPL is determined by nature. The EXPL is an observation is not manipulated or controlled. EXPL is not treatment.
Term
Confounding variable
Definition
An extraneous difference in the groups.
Term
Interacting variable
Definition
A variable that changes the way the group compare with respect to the RESP.
Term
Control group
Definition
a treatment group that receives essentially no treatment
Term
placebo
Definition
a "fake drug" that looks like a real drug but has no active ingredients.
Term
Placebo effect
Definition
the tendency of subjects to respond to any treatment, even a "fake" one.
Term
Hawthorne effect
Definition
the tendency of subjects to react differently than they normally would because they are being observed
Term
Experimenter Effect
Definition
the tendency of researchers to "see" what they want (or expect) to see.
Term
Retrospective studies
Definition
subjects are asked to recall past events
Term
Prospective studies
Definition
subjects are followed into the future
Supporting users have an ad free experience!