SOLUTION: A baseball player has a probability of 0.2 hitting the ball each time at bat, with successive times at bat being independent. Calculate the probability that he gets at least 2 h

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Question 1203053: A baseball player has a probability of 0.2 hitting the ball each time at bat, with successive times at bat being independent.
Calculate the probability that he gets at least 2 hits in 11 times at bat.
The probability is:

Answer by ikleyn(52780) About Me  (Show Source):
You can put this solution on YOUR website!
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A baseball player has a probability of 0.2 hitting the ball each time at bat,
with successive times at bat being independent.
Calculate the probability that he gets at least 2 hits in 11 times at bat.
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It is a typical problem on binomial distribution probability.

The number of trials is n= 11; 
the probability of success of each individual trial is p= 0.2;
the successful trials indexes are 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11.


    So,  P = P(2) + P(3) + P(4) + P(5) + P(6) + P(7) + P(8) + P(9) + P(10) + P(11).


Having so many calculations to do, it is better (more economic and more efficient way) 
to transform the formula equivalently

      P = 1 - P(0) - P(1) = 1+-+C%5B11%5D%5E0%2A0.2%5E0%2A%281-0.2%29%5E11+-+C%5B1%5D%5E1%2A0.2%5E1%2A%281-0.2%29%5E10 = 

        = 1+-+1%2A1%2A0.8%5E11+-+11%2A0.2%5E1%2A0.8%5E10 = 0.6779  (rounded).    ANSWER

Solved.