Help me set this up

S

siam53

New member
Joined
May 7, 2019
Messages
5
What is the probability of tossing a penny and landing on heads three times in a row?
 
I'll assume you mean that you toss it three times, and it lands on heads all three times (as opposed, say, to tossing it 100 times and some three in a row being all heads). It's important to be very clear in probability questions!

So, you are looking for P(first is heads AND second is heads AND third is heads).

What ideas do you have for doing that?
 
That is the question as written so I too am assuming that I only toss it three times. So wouldn't it be 1 out of 2 the first time, 1 chabce out of 2 the second time then 1 out of two the third time?
 
siam53 said:
What is the probability of tossing a penny and landing on heads three times in a row?
Click to expand...
I did laugh when I read this. The "probability of tossing a penny" is entirely up to you. Very difficult to calculate. :)
 
Yes, P(first is heads) = 1/2, P(second is heads) = 1/2, and P(third is heads) = 1/2.

Now how do you combine those to answer the question?
 
As Dr Peterson said the problem is unclear. If you toss a penny then it will NEVER land on heads three times in a row. It may land on heads one time or 0 times--but certainly not three times
 
siam53 said:
What is the probability of tossing a penny and landing on heads three times in a row?
Click to expand...
I disagree with others. I think that question is quite clear.
Your answer of \(\displaystyle \left(\frac{1}{2}\right)^3\) is absolutely correct.
Sometimes we have a tendency to read too much into a simple statement.
In this case it is present tense, three in a row.
A well used question is: What is the expected number of flips of a coin until the outcome is heads three times in a row?
The reason this is so popular is that it can be done with conditional probability.
 
You must log in or register to reply here.
Top