Unit 3: Statistics Flashcards
(24 cards)
Statistics
Science pertaining to collection, organization, display, analysis and/or interpretation of data
Data
Specific info collected/measured/observed
Primary data
Information collected firsthand
Secondary data
Obtained from studies conducted by other researchers
Microdata
Collected from objects and recorded
Aggregate data
Data is combined and organized into a table/graph
Qualitative/categorical data
Non numerical (in words)
Nominal
Qualitative data w/ no natural order (alphabetic doesn’t count)
Ordinal
Qualitative data w/ a natural order
Quantitative
Numerical
Discrete data
Quantitative data w/ a finite number of values (limited)
Continuous
Quantitative data w/ infinite # of of values (ex: put into intervals)
Experimental data
Data that is collected from conducting an experiment
Observational data
Data that is collected from watching something happen
Random sample
Chosen from entire population randomly (each member of pop’n has equal chance of being selected )
Voluntary sample
Members of population participate in survey on voluntary basis
Convenience sample
Selects members of population that are easily accessible
Destructive sample
Random sample taken; each destroyed during testing
Systematic sample
Members of sample chosen at regular intervals (ex: every fifth member chosen)
Stratified sample
Population divided into groups w/ similar characteristics; proportional amount chosen from each group
Strata (singular: stratum)
Groups in sample with similar characteristics; ex: age, gender, job, etc)
Cluster sample
Population divided into groups; a sample that only some of the strata pull from (ex: prom survey only asks gr. 12s)
Multi stage sample
Population divided into strata; then further divided into more strata; used several layers of clustering
Sample size depends on:
-pop’n size
- variability of pop’n
-degree of precision required in study
- sampling method chosen
