IDS 270 Midterm - UIC Sparks. Exam
Questions And Answers 100% Pass
Obervational Study - ANS We observe the behavior or ask people questions as they are going
about their day to day lives. Ex. Call people and ask them how often they eat out.
Experiement - ANS We impose some treatment on people and then observe their behavior
or ask questions. Ex. Give people a drug and then do chemical analysis of their blood.
Confounding variables - ANS Two variables where the effect of one on the dependent
variable cannot be separated from the effect of the other. Ex. If you take drugs and drink
alcohol and then have a car accident, the effect of the drugs vs. the alcohol cannot be
separated from each other as the cause of the accident.
Population - ANS The set of everything. Ex. All the people in America
Sample - ANS A small group pulled from the population. Ex. Sample 40 voters from the
population of America
Voluntary Response Sampling - ANS People volunteer to give data for a study. Ex. people text
to a phone number if they agree with a statement and text to a different one if they disagree
Convenience Sampling - ANS People are selected to be in a sample because of convenience
or low expense. Ex. Mall intercepts, or asking the people on the floor of your dorm to fill out a
survey.
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Bias - ANS Systematically favoring a certain outcome from research
Simple Random Sampling - ANS Label all the people in the population with a number. Have a
computer select a set of random numbers in that range. People labeled with the number are
selected for the sample. Therefore, every person or sub-group of people has an equal chance of
being in the sample.
Stratified Sampling - ANS First breaking the population into natural segments (called strata)
and then using random sampling within the strata. Ex. Radio stations or types of colleges
(community colleges, public universities, private universities, stand-alone liberal arts colleges)
Multi-Stage sampling - ANS Basically practicing stratified sampling repeatedly to get to a final
sample.
Under Coverage - ANS Where some members of the population cannot be selected for the
sample. Ex. People without phones if one is collecting data over the phone.
Non Response - ANS When an individual selected for the sample does not provide
information.
Response Bias - ANS Not answering truthfully when asked question about sensitive subjects.
Ex. "How much pot do you smoke"
Subjects - ANS People who are involved in an experiment.
Factors - ANS the explanatory variables in an experiment
Level - ANS the specific values that the experimenter chooses for a factor