Chapter 6: statistical distributions

• random variable

  a variable whose value depends on the outcome of an event
• discrete random variable

  a random variable which can only take certain values
• probability distribution

  fully describes the probability as a probability mass function, in the form of a table or as a diagram
• probability mass function

  example for a dice:

  • P(X=x) = 1/6, x=1,2,3,4,5,6
• probability distribution in a table

  example for a device

  A) 1

  B) P(X=x)

  C) 2

  D) 3

  E) 4

  F) 5

  G) 6

  H) 1/6

  I) 1/6

  J) 1/6

  K) 1/6

  L) 1/6

  M) 1/6

  
• discrete uniform distribution

  all outcomes are equally likely
• binomial distribution for X(formula and meaning)

  • formula: X〜B(n,p)
  • X is a random variable following a binomial distribution
  • n is the number of independent trials
  • p is the probability of success
• conditions required for binomial distributions

  • fixed number of trials
  • two possible outcomes, represented by success and failure
  • fixed probability of success
  • trials are independent of eachother
• what is the first step to doing binomial CUMULATIVE distribution on a calculator?

  adjust the question until it is <=