When you toss a fair coin, the probability of getting heads is 1/2 and the probability of getting tails is 1/2.


1. When a coin is tossed 3 times, X is the number of heads.

(a) Create a probability distribution table for the variable X.

(b) Create a probability histogram for the variable X.

(c) What is the probability of tossing 3 heads in a row? Explain.

(I need help asap pls)

 Mar 23, 2019

Since I don't know LaTeX that complicated, I will tell you the probability of rolling 0, 1, 2, and 3 heads.


When you roll 0 heads, that means you can't roll a head each time, or \(\left(\frac{1}{2}\right)^3\), which equals \(1\over8\).

When you roll 1 head, that means you roll HTT, THT, and TTH. The probably is still the same, but we multiply by 3 for each ordering, for a probability of \(3\over8\).

When you roll 2 heads, we can use the same logic to get \(3\over8\) again.

When you roll 3 heads, you get a head each time, or \(\left(\frac{1}{2}\right)^3={1\over8}\).


Hoping this helped,


 Mar 23, 2019
edited by asdf335  Mar 23, 2019

You are almost right asdf334, but you slipped up at the end! The probability of three heads is (1/2)3 = 1/8 (i.e. the same as getting no tails).

 Mar 23, 2019
edited by Alan  Mar 23, 2019

Thanks! I've edited my answer with the correction.

asdf335  Mar 23, 2019

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