IDS 270
New Edition Exam Paper
How do you calculate the average? - add all values up, divide by total number of
values
Average is the same thing as... - Mean
Observational study - 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 - 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 - 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 - The set of everything. Ex: all the people in America
Sample - A small group pulled from the population. Ex: sample 40 voters from
the population of America
Sample distribution - The set of number within one sample
, Voluntary response sampling - 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 - 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 - Systematically favoring a certain outcome from research
Simple random sampling - 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 - 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 - Basically practicing stratified sampling repeatedly to get a
final sample
Undercoverage - Where some members of the population cannot be selected for
the sample. Ex: people without phones if one is collecting data over the phone
New Edition Exam Paper
How do you calculate the average? - add all values up, divide by total number of
values
Average is the same thing as... - Mean
Observational study - 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 - 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 - 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 - The set of everything. Ex: all the people in America
Sample - A small group pulled from the population. Ex: sample 40 voters from
the population of America
Sample distribution - The set of number within one sample
, Voluntary response sampling - 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 - 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 - Systematically favoring a certain outcome from research
Simple random sampling - 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 - 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 - Basically practicing stratified sampling repeatedly to get a
final sample
Undercoverage - Where some members of the population cannot be selected for
the sample. Ex: people without phones if one is collecting data over the phone
