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Ch1. Statistics:
data, fcn’s of data(mean,range), techniques for collection analysis and interpretation of data for decision making, science of creating and
applying such techniques.
Population
: collection of all people objects or events having one or more preferred characteristics.
Element
: a
single person object or event of the pop.
Observation
: a # or label used to represent an element of the pop.
Sample
: a subset of a population which is
studied or observedany size group<than the pop. Analysis performed on sample rather than population.
Descriptive
: summarized data from a sample.
Inferential
: draws conclusions about pop based on data sample.
Random sample
: method of drawing samples from a population such that every possible
sample of a particular size has an equal chance of being selected.
Variable
: a characteristic that can take different values.
Qualitative
: consists of categories
of attributes or nonnumerical characters; unordered: makes no sense to rank categories like types of birds; ordered: categories can be ranked like grade
A,B,C,D, or F.
Quantitative
: consists of counts or numerical measurements; discrete: consists of a finite # of values or countable infinite # of values (if can
count discrete) like # of students absent; continuous: consists of uncountable infinite # of values like weight and speed.
Range:
set of elements for which the
variable stands for.
Value
: element of the range.
Constant
: characteristic that does not vary.
Measurement
: process of arranging #’s or labels to
characteristics.
Nominal
: can be all consists of
labels
which are
distinct
“names only” like movie genres, zip codes, political parties, also assigning elements
to mutually exclusive and exhaustive equivalence classes; appropriate transformation any one to one substitution (substituting 9 for 1); range of unordered
qual. variable.
Ordinal:
cannot go back wards not nominal. consists of labels that are distinct
and ordered
like product ratings of good better and best and hotel
ratings 15 stars; monotonic transformation permitting one to replace the original set of #’s with new #’s as long as the new #’s have the same order as the
original #’s; range of ordered qual. variable .
Interval
: consists of #’s which are distinct and ordered and equivalence of intervals like years (date not time) can
determine diff. b/w 2 years , does not have an absolute 0, time not begin at year 0; also like degrees F, not complete lack of warmth at 0 degrees; positive
linear transformation X’= a + bX; range of discrete quant. variable.
Ratio
: consists of #’s
, distinct and ordered equivalence of intervals, has no absolute
zero
(origin of the scale representing absence of measured characteristic), like distance in yards, o means there is no distance, 6 yds is twice of 3 yds;
transformation is multiplication be positive constant X’=bX.
National statistics
: john graunt; oldest enumerative and descriptive in character, traced to
beginning of history.
Probability theory
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 Fall '07
 kirk

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