• Standard deviation is a measure of how spread out the data is.

  • The greater the standard deviation, the greater the spread of data.

  • A normal distribution is usually a bell-shaped curve.

Characteristics of normal distribution

  • Mean, mode and median are equal
  • bell shaped
  • Symmetrical (50% higher than mean, 50% lower)
  • Most values are close to the mean
  • Few individuals at extremes