According to Brighton Webs LTD, a British company that specializes in data analysis, the arrival time of requests to a Web server within each hour can be modeled by a uniform distribution ( www.brighton-webs. co.uk ). Specifically, the number of seconds x from the start of the hour that the request is made is uniformly distributed between 0 and 3,600 seconds. Find the probability that a request is made to a Web server sometime during the last 15 minutes of the hour.

Requests to a Web server. In Exercise $4.175$ (p. 258) you learned that Brighton Webs LTD modeled the arrival time of requests to a Web server within each hour, using a uniform distribution. Specifically, the number of seconds $x$ from the start of the hour that the request is made is uniformly distributed between 0 and 3,600 seconds. In a random sample of $n=60$ Web server requests, let $\bar{x}$ represent the sample mean number of seconds from the start of the hour that the request is made. Find the probability that $\bar{x}$ exceeds 2,000 seconds.

Study of why EMS workers leave the job. A study of fulltime emergency medical service (EMS) workers published in the Journal of Allied Health (Fall 2011) found that only about 3% leave their job in order to retire. (See Exercise $3.45$, p. 158.) Assume that the true proportion of all fulltime EMS workers who leave their job in order to retire is $p=.03$. In a random sample of 1,000 full-time EMS workers, let $\hat{p}$ represent the proportion who leave their job in order to retire. Compute $P(\hat{p}>.025)$. Interpret this result.

Requests to a Web server. In Exercise $4.175$ (p. 258) you learned that Brighton Webs LTD modeled the arrival time of requests to a Web server within each hour, using a uniform distribution. Specifically, the number of seconds $x$ from the start of the hour that the request is made is uniformly distributed between 0 and 3,600 seconds. In a random sample of $n=60$ Web server requests, let $\bar{x}$ represent the sample mean number of seconds from the start of the hour that the request is made. Find the probability that $\bar{x}$ is between 1,700 and 1,900 seconds.

Write each italicized word in these sentence, then indicate whether it is used as an adjective or as an adverb.

In Tahiti, people see the web-spinning, lowly spider as a shadow of the gods.

Which are Lewis acids and which are Lewis bases?

(a) BF3 (b) ? (c) ? (d)

How does your web browser get a file from the Internet? Your computer sends a request for the file to a web server, and the web server sends back a response. For one particular web server, the time (in seconds) after the start of an hour at which a request is received can be modeled by a uniform distribution on the interval from 0 to 3600 seconds. Draw a density curve lo model the amount of time after an hour at which a request is received by the web server. Be sure to include scales on both axes.

LASIK surgery complications. According to studies, $1 \%$ of all patients who undergo laser surgery (i.e., LASIK) to correct their vision have serious postlaser vision problems (All About Vision, 2012). In a sample of 100,000 patients, what is the approximate probability that fewer than 950 will experience serious postlaser vision problems?

According to recent studies, 1% of all patients who undergo laser surgery (i.e., LASIK) to correct their vision have serious post-laser vision problems ( All About Vision , 2006). In a random sample of 100,000 LASIK patients, let x be the number who experience serious post-laser vision problems. a. Find E ( x ). b. Find Var( x ). c. Find the z -score for x = 950. d. Find the approximate probability that fewer than 950 patients in a sample of 100,000 will experience serious post-laser vision problems.

Requests to a Web server. In Exercise $4.175$ (p. 258) you learned that Brighton Webs LTD modeled the arrival time of requests to a Web server within each hour, using a uniform distribution. Specifically, the number of seconds $x$ from the start of the hour that the request is made is uniformly distributed between 0 and 3,600 seconds. In a random sample of $n=60$ Web server requests, let $\bar{x}$ represent the sample mean number of seconds from the start of the hour that the request is made. Find $\operatorname{Var}(\bar{x})$.

Timber beams are widely used in home construction. When the load (measured in pounds) per unit length has a constant value over part of a beam, the load is said to be uniformly distributed over that part of the beam. Uniformly distributed beam loads were used to derive the stiffness distribution of the beam in the American institute of Aeronautics and Astronautics journal (May 2013). Consider a cantilever beam with a uniformly distributed load between 100 and 115 pounds per linear foot. a. What is the probability that a beam load exceeds 110 pounds per linear foot? b. What is the probability that a beam load is less than 102 pounds per linear foot? c. Find a value L such that the probability that the beam load exceeds L is only .1.

Study of why EMS workers leave the job. A study of fulltime emergency medical service (EMS) workers published in the Journal of Allied Health (Fall 2011) found that only about $3 \%$ leave their job in order to retire. (See Exercise $3.45$, p. 158.) Assume that the true proportion of all fulltime EMS workers who leave their job in order to retire is $p=.03$. In a random sample of 1,000 full-time EMS workers, let $\hat{p}$ represent the proportion who leave their job in order to retire. Describe the properties of the sampling distribution of $\hat{p}$.

Load on timber beams. Timber beams are widely used in home construction. When the load (measured in pounds) per unit length has a constant value over part of a beam, the load is said to be uniformly distributed over that part of the beam. Uniformly distributed beam loads were used to derive the stiffness distribution of the beam in the American Institute of Aeronautics and Astronautics Journal (May 2013). Consider a cantilever beam with a uniformly distributed load between 100 and 115 pounds per linear foot. What is the probability that a beam load is less than 102 pounds per linear foot?

Miraculin - a protein naturally produced in a rare tropical fruit - can convert a sour taste into a sweet taste. Consequently, miraculin has the potential to be an alternative low-calorie sweetener. In Plant Science (May 2010), a group of Japanese environmental scientists investigated the ability of a hybrid tomato plant to produce miraculin. For a particular generation of the tomato plant, the amount x of miraculin produced (measured in micrograms per gram of fresh weight) had a mean of 105.3 and a standard deviation of 8.0. Assume that x is normally distributed. Find P(x > 120).