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 observed-any 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 1-5 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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