Sunday, March 15, 2009

Today in class Mr. K started off by putting us into groups. We were then given problems to solve. You can check the slide for today.

Independent and Dependent event

My understanding about
Dependent Variable it's called dependent variable because it's distribution of values depends upon the distribution of the other values or in other words It is something that depends on other factors while Independent Variable is a variable whose value determines the value of other variables or it is a variable that stands alone and isn't changed by other variable.

Here are some examples

The Probability of heads landing up when you flip a coin is 1/2
What is the probability of getting tails if you flip it again? It is still 1/2
The two events do not affect each other because it is an Independent event.

click to open the box

Two balls are drawn successively without replacement from a box which contains 4 blue balls and 3 red balls.
Find the probability that:

(a) the first ball drawn is blue and the second is red
(b) both balls are red.

The second event is dependent on the first

P(blue) = 4/7

There are 6 balls left and out of those 6, three of them are red. So the probability that the second one is red is given by:

P(red) = 3/6 = 1/2 reminder always simplify

dependent event so 4/7 × 1/2 = 2/7

Also dependent event. Using same method, but realizing there will be 2 red balls on the second draw, we have:

The next scriber I choose is : HENSON


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