Geometric Distribution Calculator

 #Trials until 1. Success n= Probability of Success p=

All you need to know about Geometric Distributions

is the Geometric Probability formula.

used when the following conditions called "BITS" are fulfilled:
B = Binary (two) outcomes are possible, called Bernoulli trials, ex: Head or Tails, Make or Miss a Free Throw.
I = The events are Independent, ex: getting a head has no impact on the outcome of the next toss.
T = Number of Trials varies. ex: we toss a coin until first head or we take the first free throws
S = Success probability is constant, ex: P(Head) = 50% or P(make free throw) = 80% = .80

Advanced Information on the Geometric Distribution: Mean= , Standard Deviation =

Sample Geometric Distribution Problem

What is the probability of making the first free throw on the 3. attempt, make probability per free throw is 80% ?
Here, n=3 (the number of trials until 1. success), p=.8 (success probability)
Plugged into the Geometric Probability formula: P(X=2)= $.8*\left(1-.8\right)\left(3-1\right)= .8*.22= .8*.04 = .032 = 3.2%$
Alternatively we can state: P(MISS, MISS then MAKE) = .2 *.2 *.8 .
Get it now? Try the above Geometric Distribution Calculator a few more times.

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