PSY201H1 Lecture Notes - Percentile Rank, Standard Score, Standard Deviation

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1 Oct 2012
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If a score is changed the mean will always change; every score is used in its calculation. Very sensitive to extreme scores: median isn"t sensitive to extremes; more appropriate when you have extreme scores, central tendency and symmetry, ex. Mean, median, mode, all of the above: median (iii) Its deviation scores add to zero: ex. What is a deviation score: only the mean"s deviation scores add to zero (iv) Its squared deviation scores, when added, are the smallest you can get (v) What does a standard deviation of 1. 5 mean: standard deviation notation. Speed to split 4 pieces of wood: you took 28s sec, group mean=32. 33 sec; group standard deviation=9. 52sec, what does a z score of -. 45 mean, putting a z score back in original units, ex. Example: your friend says she has an intelligence test score of 127: what is her percentile rank, step 1: calculate her z score. Step 2: place the z score on the normal curve.