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312-Data Analysis
AICP Data Analysis
Question | Answer |
---|---|
sample | a subset of population about which data are collected when it is too costly to collect data on entire populaiton |
Typical sample size | 1% ; larger sample sizes can lead to more accurate results |
to increase accuracy | larger sample size and random sampling |
Nominal or categorical | the measures are names or categories; e.g. democrat / republican |
Ordinal or ranking | there is an order to the different measures; socioeconomic status |
Interval | where the interval between the different measures has meaning; degrees Celsius, temperature |
Ratio | properties of interval variables as well as a clear definition of zero; height of building |
control variables | the independent variables that are not manipulated by the study but may have an impact on the outcome of a project |
Mean | arithmetic average; not always a good measure of central tendency because extreme values or outliers can distort the statics |
Median | the 50th percentile; better a measure of central tendency because it is less influenced by outliers than mean |
Variance | a measure of how spread out a distribution is |
Standard deviation | the sq root of the variance; used to describe the degree of which a distribution is spread out |
Chi square | a statics used to suggest whether ther might be a relationship b/w two nominal or categorical variables |
Linear regression | the influence of one or more independent variables on a dependent variable when certain assumptions are met |
Problem Definition | 1.define problem;2.specify boundaries of problem;3.develop fact base;4.list goals and objectives;5.identify range of solutions(alternatives);6.define potential costs and benefits;7.review problem statement and refine as appropriate |