
statistics
to collect, organize, analyze data

individuals
people or objects included in a study

variable
a characteristic to be studied (age, weight, gender, nationality, etc.)

quantative
a value or numerical measurement for operations such as addition or average

qualitative
characterizes an individual by grouping based on similarities (categorial)

population data
asking every individual in the population

sample data
data comes from some of the population (a sample of people)

nominal level of measurement
applies to data that consists of name, labels, or categories

ordinal level of measurement
applies to data that may be arranged in order. however, differences between data values either cannot be determined or are meaningless

interval level of measurement
applies to data that can be arranged in order. differences between data values are meaningful. no starting point and/or no zero

ratio level
applies to data that can be arranged in order. both differences between data values and ratios of data values are meaningful. data has a true zero

simple random sample
every member of the population has an equal chance of being included in the sample

simulation
a numerical representation of a real world phenomenon

stratified sampling
all members of the group (strata) are organized from the population based on characteristics. then a sample is drawn from the group

systematic sampling
members of the population are sequentially numbered. then, from a starting point, every kth member of the population is included in the sample

clustered
the entire population is divided into preexisting segments or clusters (often geographic). clusters are randomly selected and every cluster member is included

convenience sampling
data are used from population members that are readily available

census
measurements and observations from an entire population

sample
measurements or observations from a representative part of the population should be

observational study
observations and measurements of individuals are conducted in a way that doesn't change the response or the variable being measured

experiment
measurement is deliberately imposed on the individuals in order to observe a possible change in the response or variable being measured

placebo effect
occurs when a subject receives no treatment but (incorrectly) believes he or she is in fact receiving treatment and responds favorably


