PSY 207 Lecture Notes - Lecture 4: Variance, Central Tendency, Sample Size Determination
Document Summary
Since we have discussed measures of central tendency : now we need measures to describe the degree to which observations, cluster together or disperse or deviate. Measures that indicate the degree of difference among observations. Describes the distribution by telling us how much distance to expect between one score and another. Measures how well and individual score (or group of scores) represent the entire distribution. A measure of variability that is the distance from the lowest score to the highest score. Thus, is not fully representative of the variability for the entire distribution of scores. Examine deviations -> (x - : where you subtract the mean from each individual score. The core of variability calculations involve computing a set of deviation scores. The sign (+or-) tells us if the score is located above (+) or below (-) the mean. The number tells us the magnitude of the distance to the mean. Remember to square the deviations, not the raw scores.
