PSY 2106 Lecture Notes - Lecture 5: Interquartile Range, Standard Deviation, Observational Error
14 Nov 2018
School
Department
Course
Professor
Document Summary
The extent to which individuals data points are spread around the center. What statistics is trying to do is sort out what the causes of variability in behaviour are. Range: simply the difference between the highest and lowest score in the data set. Often too much trimmed statistics (eg 10%) Just want a measure that accurately reflects spread. A deviation is a difference between a score and the mean. However, there"s a reason we don"t do this - what is it. To get around this problem, we can take each deviation from the mean, and square it. This gets rid of our negative deviations, and prevents them from cancelling out our positive deviations. However there is a problem with the variance too - it is hard to describe exactly what i means. Solution = convert it to the standard deviation. The standard deviation is simply the positive square root of the variance.
