Loading [MathJax]/jax/output/SVG/jax.js
 
+0  
 
0
1
3056
3
avatar

How do you calculate the chance of rolling a certain number on a six sided dice once (assuming the rolls are completely random) in a certain number of rolls? Ex: rolling a dice 6 times won't get you a 100% chance of rolling a six.

 Feb 19, 2015

Best Answer 

 #3
avatar+118696 
+10

I like your graph Alan.   :)

 

what alan has done is  

 

nC1(16)1(56)n1$youcantakethisanotherstep$$Sayyouwantyourparticularnumbertoappearexactlymtimes,where$m$Thentheprobabilitywouldbe$nCm(16)m(56)nm

 

 Feb 19, 2015
 #1
avatar+118696 
+5

P (NOT rolling a particular number in n trials) = (56)n

 

so

 

P(Rolling a particular number in n trials ) =      1(56)n

 Feb 19, 2015
 #2
avatar+33654 
+5

Melody's answer assumes the probability is of the number appearing at least once.

To calculate the probability of it appearing exactly once, use (n/6)(5/6)n-1.

 

The two probabilities are compared as a function of n in the graph below:

 Probabilities:

 

(The final sentence in the question suggests that Melody's answer is what was being sought.)

.

 Feb 19, 2015
 #3
avatar+118696 
+10
Best Answer

I like your graph Alan.   :)

 

what alan has done is  

 

nC1(16)1(56)n1$youcantakethisanotherstep$$Sayyouwantyourparticularnumbertoappearexactlymtimes,where$m$Thentheprobabilitywouldbe$nCm(16)m(56)nm

 

Melody Feb 19, 2015

1 Online Users