Skewed

• Negative skew - The outliers are at the bottom of the distribution
• Positive skew - There are outliers at the top of the distribution
• If the data is skewed use the median not the mean

  If the data is skewed use standard deviation not the range
• How to know if the data is skewed:

  • Draw a histogram - if there's no picture, you can work it from knowing the mean and median
  • Normal distribution - mean, mode and median are the same
  • Mean is greater than the median, the distribution is positively skewed
  • Mean is less than the median, the distribution is negatively skewed