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Refer to Exercise 4.129. Find an interval for which the
4.129 During an eight-hour shift, the proportion of time Y that a sheet-metal stamping machine is down for maintenance or repairs has a beta distribution with α = 1 and β = 2. That is,
The cost (in hundreds of dollars) of this downtime, due to lost production and cost of maintenance and repair, is given by C = 10 + 20Y + 4Y2. Find the mean and variance of C.
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Chapter 4 Solutions
Mathematical Statistics with Applications
- The average American gets a haircut every 42 days. Is the average smaller for college students? The data below shows the results of a survey of 15 college students asking them how many days elapse between haircuts. Assume that the distribution of the population is normal.40, 37, 42, 46, 46, 28, 31, 39, 44, 31, 45, 39, 41, 42, 48What can be concluded at the the α= 0.05 level of significance level of significance? a. The test statistic= (please show your answer to 3 decimal places.) b. The p-value = (Please show your answer to 3 decimal places. c. Based on this, we should the null hypothesis. Thus, the final conclusion is that ... a.The data suggest the populaton mean is significantly lower than 42 at α= 0.05, so there is sufficient evidence to conclude that the population mean number of days between haircuts for college students is lower than 42. b.The data suggest the population mean number of days between haircuts for college students is not significantly lower than 42 at α= 0.05, so…arrow_forwardfind subparts of questionarrow_forwardSuppose a sample Y1, ..., Yn is selected from an exponential distribution with E (Yi) = θ and V (Yi) = θ2. Let θˆ be an estimator of the mean, θ.1. Explain what a parameter is. What is the parameter of interest in this case?2. Name the properties of a good estimator and explain, shortly, what is meant by each. (a)(b) (c)3. Given the properties you discussed in (2) and the parameter of interest identified in (1), what estimator would you propose?4. What would the sampling distribution of this estimator be? Why?arrow_forward
- Q3. Exponential Distribution has a memoryless property. Intuitively, it means that the probability of customerservice answering you call (assuming waiting time is exponential) in the next 10 mins is the same, no matter ifyou have waited an hour on the line or just picked up the phone. Formally, if X ∼ exponential(λ), f(x) = λ exp(-λx), and t and s are two positive numbers, use the definition of conditional probability to show thatP(X > t + s | X > t) = P(X > s).Hint: Find the cdf of X first, and note that P(X > t + s Ç X > t) = P(X > t + s)arrow_forward#6arrow_forwardFf.193.arrow_forward
- Exercise 6. The first quartile (or 25th percentile) of the distribution of X is defined as that value qo.25 such that P(X < 90.25) = 0.25. If X ~ f(x) = 4x³ 1(0 < x < 1), what is qo.25?arrow_forwardPLEASE DONT COPY ANSWERS FROM ANY OTHER SOURCES. ONLY CORRECT ANSWERS PLEASE! PLEASE DONT ANSWER IF YOU ARE NOT AWARE OF IT.arrow_forwardT2 #10 Apr 5 The lifetime X in months of a pair of walking shoes has gamma distribution with mean μ = 14.4 and standard deviation σ = 4.8. a) Find the parameters α and β of this gamma distribution. b) Find the probability that a pair of these shoes will last between 16 months and 24 months, inclusive.arrow_forward
- You have information to suggest that a certain continuous variable of a population has a mean of μ = 9.13 and a standard deviation of o = 6.67. You are to randomly pick n = 71 individuals from this population and observe the value of the population variable on each. This value is to measured as X₁. After the random sample of n = 71 has been taken, you are asked to consider the behavior of the statistic X. (a) Complete the statement below. Use as many decimals as you can. The distribution of X is approximately Normal with a mean x = 9.13 and a standard deviation x = 0.7916 (b) Find the probability that mean of the sample of n = 71 is between 8.53 and 9.53. Use at least four decimals in your z-values, and enter your answer to at least four decimals.arrow_forwarddo fast within 1hr I will rate u With explanation requirearrow_forward8arrow_forward
- Trigonometry (MindTap Course List)TrigonometryISBN:9781337278461Author:Ron LarsonPublisher:Cengage LearningGlencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill