The geometric probability density function builds upon what we have learned from the binomial distribution. In this case the experiment continues until either a success or a failure occurs rather than for a set number of trials. There are three main characteristics of a geometric experiment.
There are one or more Bernoulli trials with all failures except the last one, which is a success. In other words, you keep repeating what you are doing until the first success. Then you stop. For example, you throw a dart at a bullseye until you hit the bullseye. The first time you hit the bullseye is a "success" so you stop throwing the dart. It might take six tries until you hit the bullseye. You can think of the trials as failure, failure, failure, failure, failure, success, STOP.
In theory, the number of trials could go on forever. There must be at least one trial.
The probability,
p , of a success and the probability,
q , of a failure is the same for each trial.
p +
q = 1 and
q = 1 −
p . For example, the probability of rolling a three when you throw one fair die is
$\frac{1}{6}$ . This is true no matter how many times you roll the die. Suppose you want to know the probability of getting the first three on the fifth roll. On rolls one through four, you do not get a face with a three. The probability for each of the rolls is
q =
$\frac{\text{5}}{\text{6}}$ , the probability of a failure. The probability of getting a three on the fifth roll is
$\left(\frac{5}{6}\right)\left(\frac{5}{6}\right)\left(\frac{5}{6}\right)\left(\frac{5}{6}\right)\left(\frac{1}{6}\right)$ = 0.0804
X = the number of independent trials until the first success.
You play a game of chance that you can either win or lose (there are no other possibilities)
until you lose. Your probability of losing is
p = 0.57. What is the
probability that it takes five games until you lose? Let
X = the number of games you play until you lose (includes the losing game). Then
X takes on the values 1, 2, 3, ... (could go on indefinitely). The probability question is
P (
x = 5).
Try it
You throw darts at a board until you hit the center area. Your probability of hitting the center area is
p = 0.17. You want to find the probability that it takes eight throws until you hit the center. What values does
X take on?
1, 2, 3, 4, …
n . It can go on indefinitely.
A safety engineer feels that 35% of all industrial accidents in her plant are caused by failure of employees to follow instructions. She decides to look at the accident reports (selected randomly and replaced in the pile after reading)
until she finds one that shows an accident caused by failure of employees to follow instructions. On average, how many reports would the safety engineer
expect to look at until she finds a report showing an accident caused by employee failure to follow instructions? What is the probability that the safety engineer will have to examine at least three reports until she finds a report showing an accident caused by employee failure to follow instructions?
Let
X = the number of accidents the safety engineer must examine
until she finds a report showing an accident caused by employee failure to follow instructions.
X takes on the values 1, 2, 3, .... The first question asks you to find the
expected value or the mean. The second question asks you to find
P (
x ≥ 3). ("At least" translates to a "greater than or equal to" symbol).
Questions & Answers
anyone know any internet site where one can find nanotechnology papers?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?