Exam 6: Continuous Probability Distributions

The useful life (in years) of a shingled roof in Oregon has a uniform distribution described by the probability density function below.40% of shingled roofs in Oregon have a useful life between 27 years and how many years. 1/10 for values of x between 25 and 35 F(x) = 0 everywhere else

A uniform probability distribution is a continuous probability distribution where the probability that the random variable assumes a value in any interval of equal length is:

Incidents involving serious engine problems on the DD-340 aircraft are rare.They occur at an average rate of 3.0 per year (or .25 incidents per month).Assume all Poisson conditions are met.Compute the average time, in months, between incidents.

Charanka Solar Park in India reports that it produces an average of 16,400 kilowatt hours (kwh) of electricity per day, with a standard deviation of 2200 kwh.If this electrical output has a normal distribution, on 99% of the days we would expect the day's output to be least how many kwh.

Which of the following is NOT true of the normal probability distribution?

JewelMist.com estimates the cost of relocating its headquarters to Los Gatos, CA with a normal distribution centered on $9.5 million and having a standard deviation of $1.1 million.According to this distribution, there's a 45% chance that the cost will be between $9.5 million and $ how many million.(Make $9.5 million the lower boundary for your interval.)

Which of the following best describes the exponential distribution?

The mean of a normally distributed random variable:

In the exponential distribution the expected value (mean) and variance are the same.

The distribution produces probabilities for intervals of space, time, or distance between successive occurrences of a Poisson event.

For a standard normal distribution, find the area between z = -.67 and z = +.15.

Over a number of years, the average annual rate of return for Fidelity's Contra mutual fund has been .11 with a standard deviation of .23.Assume annual returns are approximately normally distributed around the average rate.Using this historical information as the basis for the calculations, there is a 50% probability that this fund will have a rate of return between .05 and what value.

Which of the following is NOT true of the normal probability distribution?

A probability distribution is a continuous probability distribution where the probability that the random variable assumes a value in any interval of equal length is the same for each interval.

The average (or expected) time it takes to complete a purchase at Trippler.com is 45 seconds.All the conditions for a Poisson distribution are met.Use the exponential distribution to determine the probability that it will take at least 2 minutes to complete your next Trippler.com purchase.

Shelton Products' website averages 4.0 visitors per minute.Visitor arrivals appear random and unrelated.(Assume all the Poisson conditions are met.) How likely is it that no more than 15 seconds will elapse before the next visitor arrives?

Which of the following is NOT a property of the normal probability distribution?

A continuous random variable would be an appropriate way to describe the outcome of which of the following experiments?

Approximately 68.3% of the values in a normal distribution will be within two standard deviations of the distribution mean.

Births in the US occur at an average rate of 7.5 births per minute (Source: Census.gov, 2013).Assume all the Poisson conditions are met.What is the expected time (in minutes) between one birth and the next?