Answer:
(a) The probability that the distance between two flaws is greater than 15 m is 0.2865.
(b) The probability that the distance between two flaws is between 8 and 20 m is 0.3246.
(c) The median is 8.322.
(d) The standard deviation is 12.
(e) The 65th percentile of the distances is 12.61 m.
Step-by-step explanation:
The random variable <em>X</em> can be defined as the distance between flaws on a long cable.
The random variable <em>X</em> is exponentially distributed with mean, <em>μ</em> = 12 m.
The parameter of the exponential distribution is:
The probability density function of <em>X</em> is:
(a)
Compute the probability that the distance between two flaws is greater than 15 m as follows:
Thus, the probability that the distance between two flaws is greater than 15 m is 0.2865.
(b)
Compute the probability that the distance between two flaws is between 8 and 20 m as follows:
Thus, the probability that the distance between two flaws is between 8 and 20 m is 0.3246.
(c)
The median of an Exponential distribution is given by:
Compute the median as follows:
Thus, the median is 8.322.
(d)
The standard deviation of an Exponential distribution is given by:
Compute the standard deviation as follows:
Thus, the standard deviation is 12.
(e)
Let <em>x</em> be 65th percentile of the distances.
Then, P (X < x) = 0.65.
Compute the value of <em>x</em> as follows:
Thus, the 65th percentile of the distances is 12.61 m.