APSY2216 Lecture Notes - Lecture 11: Standard Deviation

• School: Boston College
• Department: Counseling, Developmental, and Educational Psychology
• Course: APSY2216
• Professor: Marjorie Warfield

Document Summary

Summarizing variables: state and local youth risk behavior survey: Salad: majority no, 13/20 > 50% Breakfast: 3 - most common (6), 2 none. Def: attempt to quantify what we mean when we think of the (cid:498)typical(cid:499) or (cid:498)average(cid:499) score in a distribution. Doesn"t take into account all the scores. May have many scores with the same or similar frequency. Could have the same mode but different distributions. Could also have different mode but similar distribution: median. The value that cuts the distribution exactly in half, such that an equal number of scores are larger than that value as there are smaller than that value. 50th percentile (regardless of the shape of the distribution) More info than mode because it takes into account the order of the scores but not their magnitude. Could have same median but different magnitude. Most easily computed by sorting the data from smallest to largest. Median may not be an actual value in the data set.