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Unformatted text preview: STA Class 18:16:16 • 2.5 Numerical Measures of Variability o Describe the deviation of data about the mean (or other typical value) 1. Range – difference between the largest and smallest observation 2. Variance (Figure 2.51 in notes) o Computational Formula for Variance (Figure 2.52) 3. Standard Deviation—positive square root of the variance o Notation: S² = sample variance S = sample standard deviation σ² = population variance σ = population standard deviation o Properties of standard deviation Figure 2.53 o Example: Age 22 21 39 24 20 19 19 23 Figure 2.54 • 2.6 Interpreting the Standard Deviation o How many observations fall within 1 standard deviation of the mean? Within 2? Within K? STA Class 18:16:16 Notation: (Figure 2.61) In general: (figure 2.62) o Example: Age Data (Figure 2.63) Data: 22, 21, 39, 24, 20, 19, 19, 23 Mean:23.38 Standard Deviation:6.57 Within 1 standard deviation is: (10.24, 36.52) Figure 2.64Figure 2....
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This note was uploaded on 04/07/2008 for the course STA 2023 taught by Professor Bagwhandee during the Fall '07 term at University of Central Florida.
 Fall '07
 Bagwhandee
 Variance

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