PPGA 503 MIDTERM EXAM QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS VERIFIED
Observation
Captures a characteristic of interest.
Data
Collection of observations we're interested in.
Population
total set of subjects of interest
Parameter
summary measure of population data
Sample
Subset of the population we have observations for
Statistic
Summary of the sample data
Descriptive statistics
summarize and describe data
Inferential statistics
Make predictions about the population based on what we know about the sample
Variable
a measurable trait or characteristic that is subject to change under different conditions
Interval variable
, variable with meaningful numeric distance between levels
Discrete variable
Consists of separate, indivisible categories. No values can exist between two
neighboring categories.
Continuous variable
a quantitative variable that has an infinite number of possible values that are not
countable
Categorical variable
Doesn't have natural or meaningful numeric distance between levels
Ordinal variable
variable with a natural order (how do you feel about this class? excited, neutral, terrified
Nominal variable
Has no clear natural ordering
Validity
Does the measure reflect what we want to measure?
Reliability
Does the measurement produce consistent observations?
Sampling bias
non-probability issue with sampling strategy, or overcoverage
Response bias
anything in a survey design that influences responses (social desirability, working, or
interviewer effects)
Non-response bias
COMPLETE SOLUTIONS VERIFIED
Observation
Captures a characteristic of interest.
Data
Collection of observations we're interested in.
Population
total set of subjects of interest
Parameter
summary measure of population data
Sample
Subset of the population we have observations for
Statistic
Summary of the sample data
Descriptive statistics
summarize and describe data
Inferential statistics
Make predictions about the population based on what we know about the sample
Variable
a measurable trait or characteristic that is subject to change under different conditions
Interval variable
, variable with meaningful numeric distance between levels
Discrete variable
Consists of separate, indivisible categories. No values can exist between two
neighboring categories.
Continuous variable
a quantitative variable that has an infinite number of possible values that are not
countable
Categorical variable
Doesn't have natural or meaningful numeric distance between levels
Ordinal variable
variable with a natural order (how do you feel about this class? excited, neutral, terrified
Nominal variable
Has no clear natural ordering
Validity
Does the measure reflect what we want to measure?
Reliability
Does the measurement produce consistent observations?
Sampling bias
non-probability issue with sampling strategy, or overcoverage
Response bias
anything in a survey design that influences responses (social desirability, working, or
interviewer effects)
Non-response bias
