Measures of Dispersion

• Last time we talked about the "middle" of the data.
• This time we will talk about how "spread out" the data is.
• Two measurements
  • Range = high value - low value.
  • Standard Deviation
    • s in a sample
    • σ in a population
    • s = $\sqrt{\frac{\Sigma(x-\bar{x})^2}{n-1}}$
• Do some problems page 763
• Notice that if all the numbers are increased by n, the standard deviation is the same.