Question 1025114: The table shows the probability distribution for the number of heads when four coins are tossed. What is the probability that no more than two heads show on a random toss?
X = Number of Heads: 0, 1, 2, 3, 4
Probability: 0.0625, 0.25, 0.375, 0.25, 0.0625
My Work: My answer was 0.3125 because worked it out like this
P(X<2) = P(X=0) + P(X=1)
= 0.0625 + 0.25
= 0.3125
I just want to make sure that I have it right. Thank you for helping me.
Answer by Edwin McCravy(20056)   (Show Source):
You can put this solution on YOUR website!
No, the problem states "no more that 2", not "less than 2".
That's "less than or equal 2". So it's P(X ≤ 2), not P(X < 2).
P(X ≤ 2) = P(X=0) + P(X=1) + P(X=2)
= 0.0625 + 0.25 + 0.375
= 0.8675
Edwin
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