# probability

Consider three lightbulbs each of which has a lifetime that is an independent exponential random variable with parameter λ=1. The variance of the time until all three burn out is:

=

Recall that the variance of an exponential with parameter λ is 1/λ2.

1. 👍 0
2. 👎 0
3. 👁 523
1. 1/3 ?

1. 👍 0
2. 👎 1
2. 11/6 why it is wrong? could anyone explain this?

1. 👍 0
2. 👎 1
3. 1/9 +1/4 + 1 = 1.361111

1. 👍 2
2. 👎 0

## Similar Questions

1. ### Math

Suppose a baseball player had 211 hits in a season. In the given probability distribution, the random variable X represents the number of hits the player obtained in the game. x P(x) 0 0.1879 1 0.4106 2 0.2157 3 0.1174 4 0.0624 5

asked by Amanda on November 26, 2013
2. ### Statistics

Let X denote an exponential random variable with unknown parameter λ>0 . Let Y=I(X>5) , the indicator that X is larger than 5 . Recall the definition of the indicator function here is I(X>5)={1ifX>50ifX≤5. We think of Y as a

asked by Help on May 27, 2020
3. ### MATH help

Which of the following statements is true? A . The dependent variable is represented on the x-axis. B . The independent variable is also know as the output. C . The dependent variable is represented in the 2nd column of a table. D

asked by Miranda Lambert on January 12, 2016

true or false questions: a)The derivatives of the reciprocal trigonometric functions can be found using the chain rule and their related base functions. b) A sinusoidal function can be differentiated only if the independent

asked by Tina on October 31, 2014
5. ### Statistics

A certain type of lightbulb is advertised to have an average lifetime of 1,000 hours. Assume the lifetimes of these lightbulbs are approximately normally distributed with a standard deviation of 250 hours. A) Find the percentage

asked by Kerry on May 20, 2016
1. ### Statistics

Let X denote an exponential random variable with unknown parameter λ>0 . Let Y=I(X>5) , the indicator that X is larger than 5 . Recall the definition of the indicator function here is I(X>5)={1ifX>50ifX≤5. We think of Y as a

asked by Michael on June 2, 2020
2. ### math, probability

13. Exercise: Convergence in probability: a) Suppose that Xn is an exponential random variable with parameter lambda = n. Does the sequence {Xn} converge in probability? b) Suppose that Xn is an exponential random variable with

asked by diogenes on August 13, 2019
3. ### statistics

The lifetime of a type of electric bulb has expected value µ = 475 hours and standard deviation σ = 60 hours. (a) Use the central limit theorem to determine the expected value and standard deviation of the sample mean of n such

asked by Liza on April 6, 2017
4. ### statistics

Identify the given item as probability distribution, continuous random variable, or discrete random variable. The amount of time that an individual watches television. a. discrete random variable b. probability distribution c.

asked by maczindahouse on February 20, 2019
5. ### Statistics & probability

Suppose that X is an exponential random variable with parameter (and mean) equal to 1. Find the MAP estimate of X , given that there were exactly 5 blue flashes.

asked by CS on May 9, 2020
6. ### methods of research

4. Gerontologists interested in the effects of aging on reaction time have two groups of subjects take a test in which they must indicate as quickly as possible whether a probe word is a member of a previous set of words. One

asked by Tameka on September 22, 2016