PSYC 51a Lecture 4: PSYC 51A Lecture 4: Psyc 51A: Ch.4 Variability + Ch.5 Z Scores
10 Mar 2017
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Document Summary
Difference between the largest and smallest values. Yrl of xmax - lrl of xmin in a continuous variable. The range of the middle 50% of the observations. The average square distance from the mean or average sum of squares. Ss: sum of squared deviation from the mean. With m=8, you pick any two number, e. g. 7 and 14, then the last number will be fixed by 3 (7 + 14 + x = 24, x=3; m=8, n=3) For the mean to still be 8, so one number is not free to vary (thus it is fixed and depends on other two scores) while other two numbers are free to vary (the degree of freedom, n-1=3-1=2) In a sample, we know our sample mean from calculation. Then, n-1 represents the number of independent pieces of data. Can"t calculate parameters, so we use sample statistics to estimate the range of values the parameters are likely to have.
