Health Sciences 2801A/B Lecture Notes - Lecture 2: Standard Deviation
1 Oct 2017
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Scores: observed score, centered score, standardized scores (z score, t score, deviation score) Variables: sum of squares, variance, standard equilibrium, normal distribution, skewed distribution. Relationships b/w variables: sum of products, simple correlation. An observed score is a number yielded by a measurement instrument i. e. , 38 degrees c. A centered score is calculated by subtracting the mean from an observed score i. e. 38 37 = 1 degree c. It is equal to 0 when all the scores are the same (no variability) It increases as the scores are more variable sum of squares will tend to be. It equals the sum of squares divided by the number of scores minus 1. Standard deviation: a standard deviation is simply the square root of the variance. Degrees of freedom: the number of centered scores in a set that are unknown, variance has dof of (n-1) b/c centered scores always sum to 0.
