when the number of possible values is either a finite or a "countable" number
discrete
observations that have been collected
data
a collection of methods for planning experiments, obtaining data, and then organizing, summarizing, presenting, analyzing, interpreting, and drawing conclusions based on the data
statistics
the collection of data from every member of the population
census
he complete collection of all elements to be studied. the collection is complete in the sense that it includes all subjects to be studied
population
a subcollection of members selected from a population
sample
a numerical measurement describing some characteristic of a population
parameter
a numerical measurement describing some characteristic of a sample
statistic
consist of numbers representing counts or measurements
quantitative
can be separated into different categories that are distinguished by some non numerical characteristic
qualitative
esult from infinitely many possible values that correspond to some continuous scale that covers a range of values without gaps, interruptions. or jumps
continuous
ata can be arranged in some order, but differences between data values either cannot be determined or are meaningless
ordina
ike ordinal level, with additional property that the difference between any two data values is meaningful. However, data at this level do not have a natural zero starting point
interval
the interval level with the additional property that there is also a natural zero starting point. For values at this level, differences and ratios are both meaningful
ratio
observe and measure specific characteristics, but we don't attempt to modify the subjects being studied
observational
data is observed, measured, and collected at one point in time
cross-sectional
data is collected from the past by going back in time
retrospective
data is collected in the future from groups sharing common factors
prospective
occurs in an experiment when the experimenter is not able to distinguish between the effects of different factors
confounding
a technique in which the subject does not know whether they are receiving a placebo or a treatment
blinding
meaning that blinding occurred at two levels: the subject that did not know if they were getting a placebo or a treatment and the testers did not know either
double-blinding
a group of subjects that are similar in the ways that might affect the outcome of the experiment
blocks
the repetition or duplication of an experiment so that the results can be confirmed or verified
replication
members from the population are selected in such a way that each individual member has an equal chance of being selected
random sample
size n subjects is selected in such a way that every possible sample of the same size n has the same chance of being chosen
simple random sample
selecting some starting point and then selecting every kth element in the population
systematic
simply use the results that that are very easy to get
convenience
subdivide the population into at least two different subgroups that share the same characteristics, then draw a sample from each subgroup
stratified
divide the population area into sections, then randomly select some of those clusters, and then choose all members from those clusters
cluster