Basic concepts in probability
Basic Probability The likelihood (expressed as a fraction, proportion, or percentage) that a specific event will occur Common definition: p (A)=number of ways A can occur (#A) total number of outcomes (#O)
Simple Probability What is the probability of obtaining an ace from a deck of cards? Out of an entire deck of cards, what proportion are aces?
Relative Frequency Is Equivalent To Probability Grade Frequency Relative Frequency 9 2 0.06 8 6 0.19 7 5 0.16 3 0.09 4 1 0.00
Probability and the Normal Distribution The equation is
Normal Distribution The percentages of scores that fall in each of these sections
Example Adult height normally distributed = 68 inches, = 6 inches What percentage of people are taller than 80 inches? P(X>80) = ?
What proportion of the normal distribution corresponds to z-score values greater than z=+1.00