MEASURES OF VARIATION

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MEASURES OF VARIATION

• How dispersed, how spread out is the data?

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Study Guide Variation

• Browse pages 88-98 in your textbook
• One number may not represent an entire set of
  numbers well so, a cross reference is__________?
• Name 3 measures of variation
• Provide advantages and disadvantages of the range
• The measurement that helps us see how the data is
  different from the mean is____________?
• Why divide by n-1 sometimes and by N other times?
• Obtuse Ollie believes he has discovered an easier
  method for ex 5 (Big Blossom Greenhouse)
  E(8-5.5)2/7 Comment on his new
  formula
• Compare and contrast sample and population
  formulas for the mean and for standard deviation

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Study Guide

• A cross reference is the measure of
  dispersion/variation/fluctuation/spread
• The big 3 are range variance and standard
  deviation
• Adv of r easily computed hilo
  disadv doesnt tell us the distance individuals
  are from the typical/mean
• The standard deviation
• N1 is for the sample standard deviation N
  is used with population data
• Ollie is using the median, not the mean which is
  required
• The formulas for mean are the same regardless of
  whether we have sample or pop data. The formulas
  for s and little sigma are nearly the same,
  except for the denominator n--1

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More measures of Spread

• Stay tuned for the coefficient of variation CV
  which allows us to directly compare 2 separate
  groups/populations!
• And stay awake for Chebyshevs Theorem which
  works for any data and and constant gt1