PSYC 406 Chapter Notes - Chapter 2: Percentile Rank, Statistical Inference, Psychological Testing

• School: McGill University
• Department: Psychology
• Course: PSYC 406
• Professor: David Vachon

Document Summary

Statistical methods serve 2 important purposes in the quest for scientific understanding: statistics are used for purposes of description. Numbers provide summaries and allow us to evaluate some observations relative to others (above or below class average: statistics can be used to make inferences. Inferences are logical deductions about events that cannot be observed directly. Confirmatory data analysis: evaluating the clues against rigid statistical rules. Descriptive statistics: methods used to provide a concise description of a collection of quantitative information. Inferential statistics: methods used to make inferences from observations of a small group of people known as a sample to a larger group of individuals known as a population. For example, if a scale was used to measure height, we could say that fred is taller than john thereby attributing moreness to fred. However, if a coach assigned random numbers to teams this is not magnitude because these numbers do not represent a quantitative difference: equal intervals .