L1 | RANDOM VAR

• PROBABILITY

  • In between 0 and 1
  • Possibility of a thing happening
  • Chance, likelihood
• PROBABILITY EXPERIMENT

  • Based on chance
  • Results cannot be predicted with certainty
• SAMPLE SPACE

  • Set of all outcomes in an experiment
• VARIABLE

  • Representation of a value
• RANDOM VARIABLE

  • Function that associates a real number with each element in the sample space
  • Numerical description of the possible outcomes of a probability experiment
• TYPES OF RANDOM VARIABLE

  1. DISCRETE
  2. CONTINUOUS
• DISCRETE

  • Can be counted
  • Starts with the phrase of "the number of"
• CONTINUOUS

  • Assume all values in an interval
  • Measurable
  • Uses bell curve
• DISCRETE PROBABILITY DISTRIBUTION

  • List of all possible values of the random var with its corresponding probability
• • SUM OF P(x) is equal to 1
  • Probability of each value of the random var must be b/w 0 and 1
  • Sum of all probabilities of all values of the random var is ALWAYS equal to 1
• MEAN

  • Value representing the expected outcome if a probability experiment is repeated many times
• STANDARD DEVIATION 

  • Tells you how spread out the data is
  • Measure of how far each observed value is from the mean