Statistical Modelling: Relationships & Distributions Exploration
190 likes | 231 Views
Explore various relationship models such as Simple, Multiple, Logistic Regression, and other functional models. Dive into discrete and continuous distribution models like Uniform, Binomial, Poisson, Normal, and more.
Statistical Modelling: Relationships & Distributions Exploration
E N D
Presentation Transcript
Statistical Modelling Relationships Distributions
Modelling Process IDENTIFICATION ESTIMATION ITERATION VALIDATION APPLICATION
Relationships • Simple Regression Models • Multiple Regression Models • Logistic Regression Models • Other functional Models • Lagged Models
Simple Regression • Assumes one variable (x) relates to another (y) • Assumes errors cancel out • Assumes errors have constant variance • Assumes errors are independent of each other • Assumes errors are normally distributed (for testing theories)
Multiple Regression • Assumes several variables (xi) relates to another (y) • Assumes errors cancel out • Assumes errors have constant variance • Assumes errors are independent of each other • Assumes xi are independent of one another • Assumes errors are normally distributed (for testing theories)
Logistic Regression • Like multiple regression but variable to be predicted (y) is binary. • Estimates odds and log odds rather than direct effects.
Other Models Could be almost anything, common ones are: • Log of (some) variables • Polynomials • Trignometric • Power functions
Lagged Models Usually associated with time series data • Assume carry-over effects • Carry-over of variable • Carry-over of error • Tend to use simple forms
Distribution Models • Discrete • Continuous
Discrete Distributions UNIFORM • Equal chance of each and every outcome • Often a starting hypothesis
Discrete Distributions BINOMIAL • n trials • Equal chance of success in each trial (p) • Gives probability of r successes in n trials
Discrete Distributions POISSON • Random events • Fixed average (mean) rate • Gives probability that r events will occur in a fixed time, distance, space etc
Discrete Distributions GEOMETRIC • Constant probability of success (p) • Gives probability of r trials before first success
Continuous Distributions UNIFORM • Constant density of probability for all measurement values • Limited range of possible values
Continuous Distributions NORMAL • Commonest distribution assumption • Intuitive • Characterised by two parameters, mean and standard deviation • Arises from a number of theoretical perspectives
Continuous Distributions EXPONENTIAL • Complementary to Poisson • Assumes events occur randomly, at fixed mean rate • Gives probability density for time, distance, space etc until event occurs
Continuous Distributions EXTREME VALUE DISTRIBUTIONS • Weibull • Double exponential • Gumbel (or Extreme Value)