Exam 7: Continuous Probability Distributions

The exponential distribution is a probability distribution for a random variable measured as a rate of an event occurring.

Two business major students, in two different sections of an economics class, were comparing test scores. The following shows the sections' mean and standard deviation. The student in section 2 scored 75. The student's z score would be _____.

The time to fly between New York City and Chicago is uniformly distributed with a minimum of 120 minutes and a maximum of 150 minutes. What is the distribution's standard deviation?

The mean score of a college entrance test is 500; the standard deviation is 75. The scores are normally distributed. What percent of the students scored below 320?

Some normal probability distributions are positively skewed.

The weekly mean income of a group of executives is $1,000 and the standard deviation of this group is $100. The distribution is normal. What percent of the executives have an income of $925 or less?

From past history, the scores on a statistics test are normally distributed with a mean score of 70 and a standard deviation of 5. To earn a "C" on the test, a student must be in the top 25% of the class. A student would need to score at least ______ to receive a "C" grade.

A major credit card company has determined that customers charge between $100 and $1,100 per month. If the monthly amount charged is uniformly distributed, the average charge would be ______.

What is an important similarity between the uniform and normal probability distributions?

The proportion of the area under a normal curve that is to the right of z = -1.21 is _______.

After arriving at the university student medical clinic, the waiting times to receive service after checking-in follow an exponential distribution with a mean of 10 minutes. Calculate the probability a student waits more than 12 minutes.

The standard normal probability distribution is unique because it has _________.

If an average of 12 customers is served per hour, what is the probability that the next customer will arrive in 3 minutes or less?

Describe the normal distribution.

In the exponential distribution, the mean and standard deviation are equal to ______________.

For a standard normal distribution, what is the probability that z is greater than 1.75?

In a uniform distribution, with a minimum, a, and maximum, b, the probability that the random variable, x, is between a and (b - a)/2 is ___________.

The annual commissions per salesperson employed by a retailer of mobile communication devices averaged $40,000, with a standard deviation of $5,000. What percent of the salespersons earn between $32,000 and $42,000?

If an average of 12 customers is served per hour, what is the probability that the next customer will arrive in 6 minutes or less?

After arriving at the university student medical clinic, the waiting times to receive service after checking-in follow an exponential distribution with a mean of 10 minutes. How many students are served per hour?