Concept explainers
We have 100 components that we will put in use in a sequential fashion. That is, component 1 is initially put in use, and upon failure, it is replaced by component 2, which is itself replaced upon failure by component 3, and so on. If the lifetime of component i Is exponentially distributed with
Want to see the full answer?
Check out a sample textbook solutionChapter 8 Solutions
A First Course in Probability
- What does the y -intercept on the graph of a logistic equation correspond to for a population modeled by that equation?arrow_forwardThe lifespan of an oven made by General Electric (GE) has a mean life of 2.03 years, exponentially distributed. GE agrees to pay a full refund (100%) to a buyer if the oven breaks during the first 3 months following its purchase, a 50% refund if it breaks during months 3-12, and a 25% refund if it breaks between months 12-24. There is no refund for ovens that break after 24 months. If GE sells 330 ovens, how many ovens in total would they expect to provide a full or partial refund for? (Round up to the nearest whole oven) For a standard normal distribution, find: P(z > c) = 0.4395 Find c.arrow_forwardA company is planning to replace all 10,000 of the light bulbs with new energy saving bulbs. These bulbs have a lifetime that follows an exponential distribution with mean of 4,000 hours. If all the companies lights are on nine hours a day and five days a week, approximately how long will it be before the company has to replace the first bulb? Approximately how long, in weeks, will it be before they need to replace the last of these 10.000 bulb?arrow_forward
- Each day a machine is put in operation for five hours. Suppose that the number of hours of operation until failure of the machine is Exponential with mean of 4 hours. If the machine operates independently each day, the expected number of days each week that the machine would operate without failing isarrow_forwardTwo computer specialists are completing work orders. The first specialist receives 60% of all orders. Each order takes her Exponential amount of time with parameter A₁ = 4 hours ¹. The second specialist receives the remaining 40% of orders. Each order takes him Exponential amount of time with parameter 2₂ = 5 hours-¹1 (a) A certain order was submitted to first specialist 10 minutes ago, and what is the probability that it is still not ready? (b) A certain order was submitted 10 minutes ago, and it is still not ready. What is the probability that the second specialist is working on it?arrow_forwardOne of the factors that determines the degree of risk a pesticide poses to human health is the rate at which the pesticide is absorbed into skin after contact. An important question is whether the amount in the skin continues to increase with the length of the contact, or whether it increases for only a short time before leveling off. To investigate this, measured amounts of a certain pesticide were applied to 20 samples of rat skin. Four skins were analyzed at each of the time intervals 1 , 2 , 4 , 10 , and 24 hours. The amounts of the chemical (in micrograms) that were in the skin are given in the following table. Duration Amounts Absorbed 1 1.3 1.4 1.3 2.1 2 1.6 2.0 1.3 2.0 4 1.9 1.6 2.1 1.7 10 2.0 2.1 2.0 1.7 24 2.4 2.2 2.6 2.2 Can you conclude that the amount in the skin varies with time? Use the =α0.001 level of…arrow_forward
- One of the factors that determines the degree of risk a pesticide poses to human health is the rate at which a pesticide is absorbed into skin after contact. An important question is whether the amount in the skin continues to increase with the length of the contact, or whether it increases for only a short time before leveling off. To investigate this, measured amounts of a certain pesticide were applied to 20 samples of rat skin. Four skins were analyzed at each of the time intervals 1 , 2 , 4 , 10 , and 24 hours. The amounts of the chemical (in micrograms) that were in the skin are given in the following table. Duration Amounts Absorbed 1 1.7 1.8 1.3 2.1 2 1.9 2.0 1.3 2.0 4 2.2 1.6 2.3 1.7 10 2.0 2.2 1.9 1.7 24 2.3 2.5 2.6 2.2 Send data to Excelarrow_forwardA team of UMD students have invented an inhalable drug that they think will help people breathe better during hard exercise. They test the drug on 3 volunteers (A, B, and C) by measuring their levels of arterial oxygen before receiving the drug (their base level) and then after 5 and 10 minutes have elapsed, respectively. The results are listed in the table. Oxygen level [mmHg] A B C base level 847076 after 5 minutes 85 74 81 after 10 minutes 90 75 98 We want to see how the drug work (better or worse) when compared to the base level. Compute the 90% two-sided confidence intervals for the mean difference between the base level and after 5 minutes. X1b Xub X 1b -5.1783 Xub 11.8450 Compute the 90% two-sided confidence intervals for the mean difference between the base level and after 10 minutes. -1.94 ? Xx 0% 23.94 ? × 0% ? × 0% X 0%arrow_forwardResearchers have created every possible "knockout" line in yeast. Each line has exactly one gene deleted and all the other genes present (Steinmetz et al. 2002). The growth rate—how fast the number of cells increases per hour—of each of these yeast lines has also been measured, expressed as a multiple of the growth rate of the wild type that has all the genes present. In other words, a growth rate greater than 11 means that a given knockout line grows faster than the wild type, whereas a growth rate less than 11 means it grows more slowly. The growth rate of a random sample of knockout lines is 0.86, 1.02, 1.02, 1.01, 1.02, 1, 0.99, 1.01, 0.91, 0.83, 1.01 What is the standard deviation and variance of growth rate for this sample?arrow_forward
- 6. A small company can employ 3 workers. Each worker independently stays on the job for an exponentially distributed time with a mean of one year and then quits. When a worker quits, it takes the company an exponentially distributed time with a mean of 1/10 of a year to hire a replacement for that worker (independently of how long it takes to replace other workers). If the company takes in $1000 per day in revenue when it has 3 workers, $800 per day when it has 2 workers, and $500 per day when it has 0 or 1 workers, what is the company's long-run average daily revenue?arrow_forwardSuppose that the time it takes an equipment to break down after being put to use is exponentially distributed with mean 8 hours. What is the probability that the equipment will break down less than 5 hours after it has been put to use given that it has already been in use for 2 hours?arrow_forwardThe unloading dock at the warehouse of P&S Supermarket has two workers who unload their own assigned truck respecsvely. The inter arval time of trucks is exponential with a mean of 20 minutes while the unloading time per truck is exponential with a mean of 15 minutes. If a truck arrives and two workers are unloading other trucks, the arriving truck joins the line of trucks waiting for service. Assume there is enough space to accommodate essentialy any number of trucks waiting in the ine int You may use the formulas for M/M/2 Queuing Model) What is the average number of trucks in the waiting line? O a. 0.0333 Ob.0.s O. 3 Od.0,1227 Oe. 2.25arrow_forward
- Linear Algebra: A Modern IntroductionAlgebraISBN:9781285463247Author:David PoolePublisher:Cengage LearningAlgebra & Trigonometry with Analytic GeometryAlgebraISBN:9781133382119Author:SwokowskiPublisher:Cengage