The Normal Curve

• If data is "normally" distributed, then it follows the "bell curve" or normal curve.
  • In this case, the mean, median and mode are all the same thing.
• The normal curve can be used to model many different natural occurring populations.
  • The rate at which tires wear out.
  • The weights of children of a given age
  • The age life expectancy of fly.
• All of these have different means and standard deviations, but they behave the same.
• We will take a quick look at how to determine the probability of an event in normally distributed data.
  • We need to know the mean and standard deviation of population in question.
  • Given that we compute the z-score

  •       x-μ
    zx =  ---
           σ
    	

  • This gives us a value we can look up on the normal table.
    • Which tells us the population less than that given z-score.
• Based on that we can compute the section of a population that matches our outcomes.
• Do some problems.