Intro to Statistics (Mid-term exam)
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statistics -CORRECT ANSWER the science of collecting, describing, and analyzing
data
cases or units -CORRECT ANSWER subjects or objects that we obtain information
about
variable -CORRECT ANSWER any characteristic that is recorded for each case
dataset -CORRECT ANSWER a collection of variables
cases -CORRECT ANSWER stored in rows
variables -CORRECT ANSWER stored in columns
categorical variable -CORRECT ANSWER divides cases into groups with no logical
ordering
ordinal variable -CORRECT ANSWER divides cases into with a logical ordering
quantitative variable -CORRECT ANSWER measures or records a numerical quantity
for each case
population -CORRECT ANSWER includes all individuals or objects of interest
sample -CORRECT ANSWER a subset of the population
statistical interference -CORRECT ANSWER the process of using data from a sample
to gain information about the population
sampling bias -CORRECT ANSWER occurs when the method of selecting a sample
causes the sample to differ from the population in some relevant way
simple random sample -CORRECT ANSWER each unit of the population ha an equal
chance of being selected regardless of the other units chosen for the sample
bias -CORRECT ANSWER exists when the method of collecting data causes the
sample data to inaccurately reflect the population
types of bias -CORRECT ANSWER 1. response
2. wording
3. selection
, association -CORRECT ANSWER one variable tend to be related to the values of the
other variable
causation -CORRECT ANSWER changing the value of one variable influences the
value of the other variable
explanatory variable -CORRECT ANSWER causes response variable to change
confounding variable (confounding factor/lurking variable) -CORRECT ANSWER third
variable that is associated with both the explanatory variable and the response variable/
offers a plausible explanation for an association between two variables of interest
experiment -CORRECT ANSWER a study in which the research actively controls one or
more of the explanatory variables
observational study -CORRECT ANSWER a study in which the researcher does not
actively control the value of any variable but simply observes the values as they
naturally exist (impossible to avoid cofounding variable thus can not be used to
determine causality)
randomized experiment -CORRECT ANSWER he value if the explanatory variable for
each unit is determined randomly, before the response variable is measured
randomly selected sample -CORRECT ANSWER possible to generalize from the
sample to the population
not a randomly selected sample -CORRECT ANSWER cannot generalize from the
sample to the population
randomly assigned explanatory variable -CORRECT ANSWER possible to make
conclusions about causality
not a randomly assigned explanatory variable -CORRECT ANSWER cannot make
conclusions about causality
randomized comparative experiment -CORRECT ANSWER randomly assign cases to
different treatment groups and then compare results on the response variables
matched pairs experiments (two ways) -CORRECT ANSWER 1. each case gets both
treatments in a random order
2. cases get paired up in some other obvious way
purpose of matched pairs experiment -CORRECT ANSWER to compare the differences
in the response variable between the two treatments is analyzed
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statistics -CORRECT ANSWER the science of collecting, describing, and analyzing
data
cases or units -CORRECT ANSWER subjects or objects that we obtain information
about
variable -CORRECT ANSWER any characteristic that is recorded for each case
dataset -CORRECT ANSWER a collection of variables
cases -CORRECT ANSWER stored in rows
variables -CORRECT ANSWER stored in columns
categorical variable -CORRECT ANSWER divides cases into groups with no logical
ordering
ordinal variable -CORRECT ANSWER divides cases into with a logical ordering
quantitative variable -CORRECT ANSWER measures or records a numerical quantity
for each case
population -CORRECT ANSWER includes all individuals or objects of interest
sample -CORRECT ANSWER a subset of the population
statistical interference -CORRECT ANSWER the process of using data from a sample
to gain information about the population
sampling bias -CORRECT ANSWER occurs when the method of selecting a sample
causes the sample to differ from the population in some relevant way
simple random sample -CORRECT ANSWER each unit of the population ha an equal
chance of being selected regardless of the other units chosen for the sample
bias -CORRECT ANSWER exists when the method of collecting data causes the
sample data to inaccurately reflect the population
types of bias -CORRECT ANSWER 1. response
2. wording
3. selection
, association -CORRECT ANSWER one variable tend to be related to the values of the
other variable
causation -CORRECT ANSWER changing the value of one variable influences the
value of the other variable
explanatory variable -CORRECT ANSWER causes response variable to change
confounding variable (confounding factor/lurking variable) -CORRECT ANSWER third
variable that is associated with both the explanatory variable and the response variable/
offers a plausible explanation for an association between two variables of interest
experiment -CORRECT ANSWER a study in which the research actively controls one or
more of the explanatory variables
observational study -CORRECT ANSWER a study in which the researcher does not
actively control the value of any variable but simply observes the values as they
naturally exist (impossible to avoid cofounding variable thus can not be used to
determine causality)
randomized experiment -CORRECT ANSWER he value if the explanatory variable for
each unit is determined randomly, before the response variable is measured
randomly selected sample -CORRECT ANSWER possible to generalize from the
sample to the population
not a randomly selected sample -CORRECT ANSWER cannot generalize from the
sample to the population
randomly assigned explanatory variable -CORRECT ANSWER possible to make
conclusions about causality
not a randomly assigned explanatory variable -CORRECT ANSWER cannot make
conclusions about causality
randomized comparative experiment -CORRECT ANSWER randomly assign cases to
different treatment groups and then compare results on the response variables
matched pairs experiments (two ways) -CORRECT ANSWER 1. each case gets both
treatments in a random order
2. cases get paired up in some other obvious way
purpose of matched pairs experiment -CORRECT ANSWER to compare the differences
in the response variable between the two treatments is analyzed
