Exam 7: Continuous Probability Distributions

If the random variable Z has a standard normal distribution,then P(Z ≤ -1.72)is:

The mean,median,and mode of a normal distribution will always be the same.

The triangular distribution T(0,10,20)has a standard deviation of:

The time required for a citizen to complete the 2010 U.S.Census "long" form is normally distributed with a mean of 40 minutes and a standard deviation of 10 minutes.What proportion of the citizens will require less than one hour?

The area under a normal curve is 1 only if the distribution is standardized N(0,1).

The triangular distribution is used in "what-if" analysis for business planning.

Bob's z-score for the last exam was 1.52 in Prof.Axolotl's class BIO 417,"Life Cycle of the Ornithorhynchus." Bob said,"Oh,good,my score is in the top 10 percent." Assuming a normal distribution of scores,is Bob right?

If the mean waiting time for the next arrival is 18 minutes,what is the first quartile (25^th percentile)for waiting times?

If arrivals occur at a mean rate of 2.6 events per minute,the exponential probability of waiting more than 1.5 minutes for the next arrival is:

Assume that X is normally distributed with a mean μ = $64.Given that P(X ≥ $75)= 0.2981,we can calculate that the standard deviation of X is approximately:

Could this function be a PDF?

Which model best describes your waiting time until you get the next nonworking web URL ("This page cannot be displayed")as you click on various websites for Florida condo rentals?

If arrivals occur at a mean rate of 3.6 events per hour,the exponential probability of waiting less than 0.5 hour for the next arrival is:

Normal distributions differ only in their means and variances.

There is a simple formula for normal areas,but we prefer a table for greater accuracy.

For Gardyloo Manufacturing,the true proportion of accounts receivable with some kind of error is .20.If an auditor randomly samples 225 accounts receivable,what is the approximate normal probability that 39 or fewer will contain errors?

The price-earnings ratio for firms in a given industry follows the normal distribution.In this industry,a firm whose price-earnings ratio has a standardized value of z = 1.00 is approximately in the highest ______ percent of firms in the industry.

The triangular distribution T(5,23,62)has a mean of:

A large number of applicants for admission to graduate study in business are given an aptitude test.Scores are normally distributed with a mean of 460 and standard deviation of 80.The top 2.5 percent of the applicants would have a score of at least (choose the nearest integer):

A large number of applicants for admission to graduate study in business are given an aptitude test.Scores are normally distributed with a mean of 460 and standard deviation of 80.What fraction of the applicants would you expect to have a score of 400 or above?