# probability

• Jun 2nd 2007, 12:45 PM
bay
probability
A bag of marbles contains two colours: red and blue. Two marbles are drawn from the bag and colors are recorded. This experiment is performed 12 times. Determine the approximate probability that 2 red marbles are drawn from the bag

My answer: the probability is 6 :)
• Jun 2nd 2007, 12:49 PM
Jhevon
Quote:

Originally Posted by bay
A bag of marbles contains two colours: red and blue. Two marbles are drawn from the bag and colors are recorded. This experiment is performed 12 times. Determine the approximate probability that 2 red marbles are drawn from the bag

My answer: the probability is 6 :)

just the nature of your answer should tell you that it's incorrect. you can't have a probability greater than 1. now the chart tells you the frequency of choosing the different combinations: 2 reds, 1 red 1 blue, or 2 blues. Note that all these frequencies add up to 12. now the chart says that the frequency of choosing 2 red marbles is 6. it means out of 12 trials, we would get 2 red marbles approximately 6 out of those 12 times we do the experiment. so now, what do you think the probability is?
• Jun 2nd 2007, 01:04 PM
bay
well...
I see now that you pointed it out it was a dumb mistake and i belive the the probablitiy is 1/2 = 0.5
Is this correct?
• Jun 2nd 2007, 01:06 PM
Jhevon
Quote:

Originally Posted by bay
I see now that you pointed it out it was a dumb mistake and i belive the the probablitiy is 1/2 = 0.5
Is this correct?

correct, it is 6/12 = 1/2 = 0.5