Exam 6: Continuous Random Variables

The flying time of a drone airplane has a normal distribution with mean 4.76 hours and standard deviation of .04 hours.What is the probability that the drone will fly: Between 4.70 and 4.82 hours?

A set of final examination grades in a calculus course was found to be normally distributed with a mean of 69 and a standard deviation of 9. What percentage of students scored between 65 and 89?

Which of the following statements is not a property of the normal probability distribution?

The z-value tells us the number of _____ that a value of x is from the mean.

During the past six months,73.2% of US households purchased sugar.Assume that these expenditures are approximately normally distributed with a mean of $8.22 and a standard deviation of $1.10.What proportion of the households spent between $5.00 and $9.00?

Suppose that the waiting time for a license plate renewal at a local office of a state motor vehicle department has been found to be normally distributed with a mean of 30 minutes and a standard deviation of 8 minutes.Suppose that in an effort to provide better service to the public,the director of the local office is permitted to provide discounts to those individuals whose waiting time exceeds a predetermined time.The director decides that 15% of the customers should receive this discount.What are the numbers of minutes they need to wait to receive the discount?

An apple juice producer buys all his apples from a conglomerate of apple growers in one northwest state.The amount of juice squeezed from each of these apples is approximately normally distributed with a mean of 2.25 ounces and a standard deviation of 0.15 ounce. What is the probability that a randomly selected apple will contain between 2.00 and 3.00 ounces?

Find z when the area to the left of z is .6700

The standard deviation of a standard normal distribution is always equal to 1.

The normal probability distribution is a discrete probability distribution.

Suppose the distribution of personal daily water usage in New York City is normally distributed with a mean of 15 gallons and a variance of 25 gallons.Because of a current problem with the distribution of water to its citizens,the mayor wants to give a city tax rebate to the 15 percent of the population who use the least amount of water.What should he use as the water limit for a person to qualify for a city tax rebate?

The standard deviation of a standard normal distribution is always equal to _____.

The lifetime of a stereo component is exponentially distributed with mean 1,000 days.What is the probability that the lifetime: Is greater than or equal to 700 days?

A property of continuous distributions is that:

At an ocean-side nuclear power plant,seawater is used as part of the cooling system.This raises the temperature of the water that is discharged back into the ocean.The amount that the water temperature is raised has a uniform distribution over the interval from 10 to 25ºC. What is the standard deviation of the temperature increase?

While conducting experiments,a marine biologist selects water depths from a uniformly distributed collection that vary between 2.00 m and 7.00 m.What is the expected value of the water depth?

During the past six months,73.2% of US households purchased sugar.Assume that these expenditures are approximately normally distributed with a mean of $8.22 and a standard deviation of $1.10. Find the probability that a household spent less than $5.00

The yearly cost of dental claims for the employees of the local shoe manufacturing company is normally distributed with a mean of $105 and a standard deviation of $35.What is the yearly cost at which 35% of the employees fall at or below?

The weight of a product is normally distributed with a mean of four ounces and a variance of .25 "squared ounces." What is the probability that a randomly selected unit from a recently manufactured batch weighs no more than 3.5 ounces?

The weight of a product is normally distributed with a mean of four ounces and a variance of .25 "squared ounces." The company wants to classify the unit as a scrap in a maximum of 1% of the units if the weight is below a desired value.Determine the desired weight such that no more than 1% of the units are below it.