PO218 Lecture Notes - Lecture 3: Collectively Exhaustive Events, Nominal Level, Statistical Inference
Document Summary
The role of statistics in the research process. Statistics are mathematical tools used to organize, summarize, and manipulate data. Statistics are tools to understand differences between categories. Data are scores on variables, or information expressed as numbers (quantitatively) Univariate descriptive statistics include: percentages, averages, charts and graphs. Example: students have an average gpa of 3. 1. Bivariate descriptive statistics describe the strength and direction of the relationship between two variables. Older students tend to have a higher gpa for females but not for males. Generalize, or infer, from a sample to a population. Population includes all cases in which the research is interested. Samples include carefully (randomly) chosen subsets of the population. Voter surveys are a common application of inferential statistics. A thousand or so carefully (randomly) selected voters are interviewed about their voting intentions. This information is used to estimate the intentions of all voters (millions of people) Example: the liberal party will receive about 39% of the vote.
