国外社会科学统计distributions.pptVIP

Statistics for the Social Sciences Psychology 340 Fall 2006 Outline (for week) Variables: IV, DV, scales of measurement Discuss each variable and it’s scale of measurement Characteristics of Distributions Using graphs Using numbers (center and variability) Descriptive statistics decision tree Locating scores: z-scores and other transformations Let’s get some data On a sheet of paper (that you’ll turn in) write out these pieces of information: Male or female Height (in inches) How many pairs of shoes in your closet Typical number of servings of soda per day Typical number of servings of water per day Basic Concepts Variable A condition or characteristic that can have different values Value A possible number or category that a score can have Score A particular person’s value on a variable Basic Concepts Kinds of Variables A condition or characteristic that can have different values Experiment: Independent - manipulated by experimenter Dependent - measured by experimenter Observational: Explanatory - observed variable to do the explaining Response - variable to be predicted Measurement Properties of our measurement? Units of measurement - whether the measurement has a minimum sized unit or not Levels (Scales) of measurement - the correspondence between the numbers representing the properties that we’re measuring Units of Measurement Continuous variables Variables can take any number and can be infinitely broken down into smaller and smaller units E.g., For lunch I can have Units of Measurement Continuous or discrete?: Male or female Height (in inches) How many pairs of shoes in your closet Typical number of servings of soda per day Typical number of servings of water per day Levels (scales) of measurement Nominal Scale: Consists of a set of categories that have different names. Measurements on a nominal scale label and categorize observations, but do not make any quantitative distinctions between observations. Example: Eye color: Levels of measurement Ordinal Sc