Statistics Ch.1: Variables & Measurement

Types Statistics: –Descriptive –Inferential Data: Collections of observations –Population –Sample

Data & Measurement Qualitative Data -> Nominal Measurement –Names, categories, groups, attitudes… Ranked Data -> Ordinal Measurement –Placement, relative standing, Olympic medals…

Data & Measurement Quantitative Data-> Interval/Ratio Measurement –Amount or count, equivalent differences: Weight, height, temperature, test scores, income… Ratio = Interval + an absolute 0

Variables Discrete vs Continuous Independent vs Dependent Confounding

Experimental Design Experiments –Random assignment Observational Studies –Random sampling

What is the pattern of scores? Graphs often make it easier to see certain characteristics and trends in a set of data. –Graphs for quantitative data. Stem and Leaf Display Histogram Frequency Polygon –Graphs for qualitative data. Bar Chart Pie Chart number/count class/category

Shapes of Distributions

Misleading Graphs

HW 1 Appendix A: Pretest, read, Posttest Find a study (internet, paper, tv, etc) –Summarize in a paragraph –Identify key terms from ch. 1: Population or sample? Inferential or descriptive? Random sampling/assignment? Data & measurement? Discrete/continuous variable(s)? Experiment/observational study? Independent, dependent, confounding variables