PSYC 1010 Chapter Notes - Chapter 4: Standard Deviation, Central Tendency

• School: York University
• Department: Psychology
• Course: PSYC 1010
• Professor: Rebecca Jubis

Document Summary

In descriptive, experimental and correlational research, stats are tools that help us see and interpret what the unaided eye might miss. Off-the-top-of-the-head estimates often misread reality and then mislead the public: ex. Easy to design graph to make a difference look big or small: secret lies in how you label the vertical scale, read scale labels and note their range. A single score that represents a whole bunch of scores. Simplest measure is mode most frequent value. Most familiar is mean arithmetic average, obtained by adding all the scores and dividing by the number of scores. Median middle score, 50th percentile half the scores are above it and half are below: scores arranged in order. What happens to mean if distribution is lopsided: mean can be biased by a few extreme scores. Always note which measure of central tendency is reported: if it is mean consider whether a few atypical scores could be distorting it.