Introduction to Statistics

stochastic Sample each member of the population has the same chance of creation selected Representative Sample characteristics should represent those of the target population without bias experimental Study no intervention by the investigator, no treatment enforce Experimental Study Investigator has some control over the determiner Variables Categorical each observation falls into a feline flesh of groups Nominal named variables with no implied order e. G. Personality type Ordinal classify variables with implied order e. G. Veil of education Continuous measured variables Discrete government issue discrete values e. G. Number of children Numerical can assume either value within a certain range/elemental e. G. raising Types of Designs True experiment researcher has potential to randomly allocate observations to controls Quasi-experiment show a sex actship amidst an IV/DVD researcher makes manipulation of naturally occurring groups, cant make cause and effect statements Non-experiments (correlation design) question If there Is a relationship in the midst of variables, cant make cause & effect statementsBetween groups two groups existence compared on some outcome measure Within-subjects participants experience each condition of an IV, with measurements of some outcome taken on each occasion incorporeal variables variable present In an experiment, which might Interfere with the relationship between IV & DVD Confounding variables mediating variable that can adversely concern the relation between IV/DVD Internal validity expiration to which a casual relationship can be assumed between IV & DVD.External validity degree to which you can generalize the results of your study to mum underlying population T-test One sample t-test A data should spread out from a normal population Paired t-test -A must be independent, bone up from a normal distribution & populations of same spreads Independent sample A normally distributed, homogeneity of variances, independence of the observations Correlation/Regression A the relation in the population is linear, the residuals in y have a unbroken standard deviation and the residuals arise from a normal distribution detests of high-priced fit and test of independence A expected count has to be larger than five