Statistics

By: Isabella Hagen

Definitions:

-Independent Event: Is when one event has no effect on the other event.

-Dependent Event: Is when the outcome of first event effects the outcome of the second event.

Examples:

-Independent Events:

  • You flip a coin and get heads and you flip a second coin and get tails.
  • The probability of a pop quiz today and the probability of rain today.
-Dependent Events:

  • The chance that you are hungry and the chance that you are eating right now.
  • You draw a black card from a deck of cards and then draw a second black card without replacing the first card.

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Example Problems:

-Independent Event:

  • At a high school, 50% of students are on the honor roll and 10% of students have a part time job. If one student is selected at random, find P(honor roll and part time job).
  • To solve this problem you would multiply 50/100 by 10/100 to get 500/1000 or 1/2. So your answer to this problem is 1/2.
-Dependent Event:

  • A box contains 3 red buttons and 7 blue buttons. What is the probability of drawing 2 red buttons and 3 blue buttons in succession, if you so not replace the buttons after they are drawn.
  • To solve this problem you would multiply 3/10*2/9*6/8*5/7*4/6 to get 720/30240 or 1/42. So your answer to this problem is 1/42.