IDS 270 - Exam #1 Questions And Answers
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How do you calculate the average? - ANS add all values up, divide by total number of values
Average is the same thing as... - ANS Mean
Observational study - ANS We observed the behavior or ask people questions as they're
going about their day-to-day lives. Ex: call people and ask them how often they eat out.
Experiment - 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.
Confounded 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 drug versus 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
Sample distribution - ANS The set of number within one sample
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Voluntary response sampling - ANS People volunteer to give data for a study. Ex: people text
a phone number if they agree with a statement and text 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
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, standalone liberal art colleges).
Multi-stage sampling - ANS Basically practicing stratified sampling repeatedly to get a final
sample
Undercoverage - 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 questions about sensitive subjects.
Ex: "how much pot do you smoke?"