Probabilistic and Statistical Techniques 1 Revision Eng. Ismail Zakaria El Daour 2010

2 Probabilistic and Statistical Techniques A famous fast-food restaurant has a menu that consists of ten entrees, five vegetables, four kinds of juice, and three deserts. How many different meals ( consisting of one entrée, vegetable, juice and dessert) can be ordered at this restaurant? Example 1 No. of meals = 10*5*4*3 = 600 different meals

3 Probabilistic and Statistical Techniques Example 2 A procedure consists of tossing a coin, then rolling a die. What is the probability of getting a 5, given that the coin toss resulted in head Probability = 1/6

4 Probabilistic and Statistical Techniques A quick quiz consists of three multiple choice questions, each with five possible answer, only one of which is correct. If you make random guesses for each answer, what is the probability: - That all three of your answers are wrong? - Of getting at least one correct? Example 3 Probability = Probability of none correct = Probability of at least one correct = 1- none

5 Probabilistic and Statistical Techniques A ball is drawn at random from a box containing one red and one white ball. If the white ball is drawn, it is put back into the box. If the red ball is drawn, it is returned to the box together with two more red balls. Then a second draw is made. What is the probability a red ball was drawn on both the first and the second draws? Example 4 Probability =

6 Probabilistic and Statistical Techniques If a couple plans to have eight children, find the probability that they are all of the same gender Example 5 Probability (boys or girls ) = P(boys) + P(girls) =

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