Arepresentative of a high-speed internet provider calls customers to assess their satisfaction with the service. it takes her 6 seconds to turn on a phone and dial a number; then 3 additional seconds to detect a busy signal, or 25 additional seconds to wait for 5 rings and conclude that no one will answer; and 1 second to end a call. after an unsuccessful call, she re- dials (in the course of several days) until the customer answers or she has dialed four times. the outcome of each dialing is determined in an identical way: the customer being called is using the line with probability 0.2; or is unavailable to answer the call with probability 0.3; or is available and can answer the call within x seconds, which is a continuous random variable with the mean of 12 seconds and the exponential distribution. let w denote the total time spent by the representative on calling one customer. your objective is to estimate several statistics of w. toward this end, perform the following. 1. formulate a model of the calling process. 1.1 define notation for all the elements of the model. 1.2 write the expression for the cumulative distribution function of x, and derive the expression for its inverse. 1.3 draw the tree diagram of the calling process.

Overproduction of uric acid in the body can be an indication of cell breakdown. this may be an advance indication of illness such as gout, leukemia, or lymphoma.† over a period of months, an adult male patient has taken nine blood tests for uric acid. the mean concentration was x = 5.35 mg/dl. the distribution of uric acid in healthy adult males can be assumed to be normal, with σ = 1.87 mg/dl. (a) find a 95% confidence interval for the population mean concentration of uric acid in this patient's blood. what is the margin of error? (round your answers to two decimal places.) lower limit upper limit margin of error (b) what conditions are necessary for your calculations? (select all that apply.) σ is unknown n is large σ is known normal distribution of uric acid uniform distribution of uric acid (c) interpret your results in the context of this problem. there is not enough information to make an interpretation. the probability that this interval contains the true average uric acid level for this patient is 0.05. the probability that this interval contains the true average uric acid level for this patient is 0.95. there is a 95% chance that the confidence interval is one of the intervals containing the population average uric acid level for this patient. there is a 5% chance that the confidence interval is one of the intervals containing the population average uric acid level for this patient. (d) find the sample size necessary for a 95% confidence level with maximal margin of error e = 1.10 for the mean concentration of uric acid in this patient's blood. (round your answer up to the nearest whole number.) blood tests