PSYC-2101 Chapter Notes - Chapter 4: Squared Deviations From The Mean, Central Tendency, Standard Deviation

• School: University of Winnipeg
• Department: PSYCHOLOGY
• Course: PSYC-2101
• Professor: P.Pearson

Document Summary

Arithmetic mean: add up all scores and divide by number of scores, mean is sensitive to the exact value of all the scores in the distribution, the sum of the deviations about the mean equals zero. Written out: : the mean is sensitive to extreme scores, the sum of the squared deviations of all the scores about their mean is a minimum. Written out: 2 is a minimum: under most circumstances, of the measures used for central tendency, the mean is least subject to sampling variation. The overall mean: used to calculate the mean of all scores when presented with the mean of several different groups, ex. There are three groups; the first includes 50 subjects with a mean of 75, the second includes 40 subjects with a mean of 80, and the third includes 25 subjects with a mean of 70. The median (mdn): the scale below which 50% of the scores fall.