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Statistics LibreTexts

5.3: Conditional Probability Demonstration

  • Page ID
    2105
  • Skills to Develop

    • Compute conditional probabilities

    Instructions

    The simulation shows a set of \(30\) objects varying in color (red, blue, and purple) and shape (\(X\) and \(O\)). One of the objects is to be chosen at random. The various possible conditional probabilities are shown below the objects. Click on one to see how the conditional probability is computed. For example, if you click on P(X|Red) which is read "the probability of \(X\) given Red" then a box is put around each of the red objects. Of these, those that are \(X's\) are shaded. The probability of \(X\) given it is red is the number of red \(X's\) (shaded boxes) divided by the total red items (the number of boxes).

    Click "Another Example" for new distribution of objects.

    Illustrated Instructions 

    This demonstration starts by presenting you with a dataset of red, blue and purple \(Xs\) and \(Os\) (see screenshot below).

    conditional_demo1.jpg 

    Figure \(\PageIndex{1}\): Conditional Probability demo

    Selecting one of the conditional probabilities changes the display to show you how this probability would be calculated from the provided data.

    The screenshot below shows the conditional probability for getting a selection being Blue given that it is a \(O\). The demonstration shows Puts a square around all \(19\) \(Os\) in the data and a shaded square around the \(5\) blue \(Os\).

    conditional_demo2.jpg

    Figure \(\PageIndex{2}\): Conditional probability for getting a selection being Blue

    Click "Another Example" for new distribution of objects. 

    Contributor

    • Online Statistics Education: A Multimedia Course of Study (http://onlinestatbook.com/). Project Leader: David M. Lane, Rice University.