Using the geometric probability distribution after 500 trials, determine the following probabilities:


  1. $P(X=1) = 0.176$
  2. What is $P(X>1)$?



\multirow{8}{*}{}
XP(X)

10.175

20.158

30.105

40.106

50.078

60.052

70.034

Number of Trials
80.042

\multirow{2}{*}{500}
90.045

100.025


Verified Answer :

  • The sum of all probabilities in a discrete distribution is equal to 1.
  • The probability of the event \(X > 1\) is the complement of the event \(X = 1\).
  • Using the provided value \(P(X=1) = 0.176\), we calculate the probability as \(1 - 0.176\).
  • The final result is \(\boxed{0.824}\).

Explanation

  1. Understanding the probability distribution property

To find the probability \(P(X > 1)\), we first understand the fundamental property of discrete probability distributions: the sum of the probabilities of all possible outcomes for a random variable \(X\) is equal to \(1\). Mathematically, this is expressed as:
\[\sum_{x=1}^{\infty} P(X=x) = 1\]
In our case, the variable \(X\) represents the outcome of a geometric trial, and we are interested in the probability that \(X\) takes any value greater than \(1\). This can be partitioned into the event where \(X=1\) and the event where \(X > 1\). Therefore:
\[P(X=1) + P(X > 1) = 1\]

  1. Calculating the probability P(X > 1)

From the problem statement, we are given the specific probability for the first outcome:
\[P(X=1) = 0.176\]
We can now rearrange our fundamental equation to solve for the target probability \(P(X > 1)\):
\[P(X > 1) = 1 - P(X=1)\]
Substituting the given value into the equation, we perform the subtraction:
\[P(X > 1) = 1 - 0.176\]
\[P(X > 1) = 0.824\]

Examples

In statistics, this calculation is used to determine the probability of "success" occurring after the first attempt. For example, if you are analyzing how many attempts it takes for a customer to make a purchase, and you know the probability of them purchasing on the very first visit is \(17.6\%\), you can quickly determine the probability of them returning for a second or later visit as \(1 - 0.176 = 0.824\), or \(82.4\%\). This helps businesses predict customer engagement and retention strategies.