Chapter 2,3,4: Location+spread, data, correlation

• how do you calculate variance with $Sₓₓ$


  Sxx / n
• how do you calculate standard deviation

  square root of variance
• way to remember how to calculate variance

  msmsm
• cleaning data

  the process of removing anomalies
• outliers

  extreme data. can be found using

  • x>Q3+1.5(IQR) or
  • x<Q1-1.5(IQR)
• histogram formula

  k x frequency density x class width
• appearance of a frequency polygon

  a jagged line connecting where the top middle of histogram bars would be
• what do you include when comparing data?

  include:

  • one comparison of location (ie mean, median or mode)
  • one comparison of spread (ie range or variance)
• causal

  one factor causes a change in another factor. correlation does not prove a causal relationship
• what does b represent in y=a+bx in terms of regression?

  the change in y for a unit increase in x
• interpolation

  data inside data range, it is reliable
• extrapolation


  data outside data range, it is unreliable