IDS 270 EXAMS PAPER QUESTIONS AND
ANSWERS SURE A+
✔✔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, stand-alone
liberal arts colleges)
✔✔Multi-Stage sampling - ✔✔Basically practicing stratified sampling repeatedly to get
to 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.
✔✔Non response - ✔✔When an individual selected for the sample does not provide
information.
✔✔Response bias - ✔✔Not answering truthfully when asked question about sensitive
subjects. Ex. "How much pot do you smoke"
✔✔Subjects - ✔✔People who are involved in an experiment.
✔✔Factors - ✔✔explanatory variable
✔✔Level - ✔✔combination of specific values through a number of factors
✔✔Treatment - ✔✔A unique combination of levels of factors given to a set of subjects
See note above for Factors.
✔✔Interaction - ✔✔
ANSWERS SURE A+
✔✔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, stand-alone
liberal arts colleges)
✔✔Multi-Stage sampling - ✔✔Basically practicing stratified sampling repeatedly to get
to 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.
✔✔Non response - ✔✔When an individual selected for the sample does not provide
information.
✔✔Response bias - ✔✔Not answering truthfully when asked question about sensitive
subjects. Ex. "How much pot do you smoke"
✔✔Subjects - ✔✔People who are involved in an experiment.
✔✔Factors - ✔✔explanatory variable
✔✔Level - ✔✔combination of specific values through a number of factors
✔✔Treatment - ✔✔A unique combination of levels of factors given to a set of subjects
See note above for Factors.
✔✔Interaction - ✔✔
