# The time required for a citizen to complete the 2000 u.s. census

The time required for a citizen to complete the 2000 u.s. census.

Question 1

The time required for a citizen to complete the 2000 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?

Question 2

If the random variable Z has a standard normal distribution, then P(Z ≤ -1.37) is

Question 3

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, I’m in the top 10%.” Is he right?

Question 4

If arrivals occur at a mean rate of 1.6 events per minute, the exponential probability of waiting less than 1 minute for the next arrival is

Question 5

The lengths of brook trout caught in a certain Colorado stream have a mean of 14 inches and a standard deviation of 3 inches. The first quartile for the lengths of brook trout would be

Question 6

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

Question 7

If arrivals follow a Poisson distribution with mean 1.2 arrivals per minute, find the 75th percentile of waiting times (i.e., 75 percent below).

Question 8

The MPG (miles per gallon) for a certain compact car is normally distributed with a mean of 31 and a standard deviation of 0.8. What is the probability that the MPG for a randomly selected compact car would be less than 32?

Question 9

A letter is mailed to a sample of 500 homeowners. Based on past experience, the probability of an undeliverable letter is 0.06. The normal approximation to the probability of 40 or more undeliverable letters is

Question 10

Which model best describes your waiting time until you get the next non-working web URL (“This page cannot be displayed”) as you click on web sites for Florida condo rentals?

The time required for a citizen to complete the 2000 u.s. census