Probability How likely it is that something will happen.

  • Published on
    21-Jan-2016

  • View
    22

  • Download
    0

Embed Size (px)

DESCRIPTION

Probability How likely it is that something will happen. p: symbol to represent the probability of a particular outcome. # of ways an event can occur p = total # of events. The event: rolling a 3 with one die 1 (# of ways the event occurs) p = - PowerPoint PPT Presentation

Transcript

  • Probability

    How likely it is that something will happen.

  • p: symbol to represent the probability of a particular outcome.

  • # of ways an event can occurp = total # of events

  • The event: rolling a 3 with one die

    1 (# of ways the event occurs) p = 6 ( total # of possible events)

  • Event: rolling a 5 with a pair of dice

    # of ways the event can occur: 4 1 4 2 3 3 2 4 1

  • Total # of events : 36

    1 1 2 1 3 1 4 1 5 1 6 11 2 2 2 3 2 4 2 5 2 6 21 3 2 3 3 3 4 3 5 3 6 31 4 2 4 3 4 4 4 5 4 6 41 5 2 5 3 5 4 5 5 5 6 51 6 2 6 3 6 4 6 5 6 6 6

  • Probability of rolling 5 with a pair of dice

    4 (# of ways the event can occur) p = 36 (total number of events)

    1 p= p = .11 9

  • All events: 50 pieces of paper 10 green 20 red 15 yellow 5 blue

    (papers are returned after each draw)

  • 1) Prob. of two events both occurring Event A and Event B ( Prob. A) (Prob. B)

  • Event: drawing a red and a yellow

  • All events: 50 pieces of paper 10 green 20 red 15 yellow 5 blue

    (papers are returned after each draw)

  • Event: drawing a red and a yellow

    prob of red and prob of yellow 20 15 50 50

  • 20 15 300 3 50 50 2500 25

    or: 2 3 6 3 5 10 50 25

    p = .12

  • Probability does not have memory !

    If the event is defined as two draws then this method applies.

    If the event is limited to the second draw only, the probability is based on that event alone

  • 2) The probability of either of two mutually exclusive events occurring is the sum of their probabilities. Prob A or Prob B (Prob A ) + (Prob B)

  • Event: in one draw, choosing a yellow or red.

  • All events: 50 pieces of paper 10 green 20 red 15 yellow 5 blue

    (papers are returned after each draw)

  • Event: in one draw, choosing a yellow or red.

    20 15 35 7 50 50 50 10

    p = .7

  • Mutually Exclusive:When two events can not co-occur.

  • Events that are not mutually exclusive:

    Using a standard deck of 52 playing cards,Drawing a face card or a heart.

    12 faces cards13 hearts3 cards that are face cards and hearts

  • Prob A + Prob B - (Prob AB)

    12 13 3 52 52 52

Recommended

View more >