Psychology 2800E Lecture Notes - Lecture 3: Simple Random Sample, Hat, Systematic Sampling

• School: Western University
• Department: Psychology
• Course: Psychology 2800E
• Professor: Glen Gorman

Document Summary

Ways to measure variables: categorical: gender, ethnicity, etc, quantitative: Ordinal: meaningful values but unequal intervals between units. Interval: equal intervals between units but no meaningful zero. Ratio: equal intervals and a meaningful zero. Reliability of measurement: test-retest reliability: people get consistent scores every time they take the test. Internal reliability: people give consistent scores on every item of a questionnaire. The extent to which multiple measures, or items, are all answered the same. Interrater reliability: two coders" ratings of a set of targets are consistent with each other. Correlation coefficient (r): the strength of the correlation. Ranges from -1. 00 (perfectly negative) to +1. 00 (perfectly positive). The larger the absolute value of the number (closer to 1. 00), the stronger the correlation. The direction of the correlation (+ or -) is indicated by the sign. Interrater reliability and internal reliability should be 0. 7 or higher: pearson"s r only works with two variables. Validity of measurement: subjective ways to assess validity.