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WebAssign for Devore's Probability and Statistics for Engineering and the Sciences, 9th Edition [Instant Access], Single-Term
9th Edition
ISBN: 9780357893104
Author: Devore; Jay L.
Publisher: Cengage Learning US
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Textbook Question
Chapter 5, Problem 89SE
a. Use the general formula for the variance of a linear combination to write an expression for V(aX + Y). Then let a = σY/σX, and show that ρ ≥ –1. [Hint: Variance is always ≥ 0, and Cov(X, Y ) = σX · σY · σ.]
b. By considering V(aX – Y ), conclude that ρ ≤ 1.
c. Use the fact that V(W) = 0 only if W is a constant to show that ρ = 1 only if Y = aX + b.
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Chapter 5 Solutions
WebAssign for Devore's Probability and Statistics for Engineering and the Sciences, 9th Edition [Instant Access], Single-Term
Ch. 5.1 - Prob. 1ECh. 5.1 - A large but sparsely populated county has two...Ch. 5.1 - A certain market has both an express checkout line...Ch. 5.1 - Return to the situation described in Exercise 3....Ch. 5.1 - The number of customers waiting for gift-wrap...Ch. 5.1 - Let X denote the number of Canon SLR cameras sold...Ch. 5.1 - Prob. 7ECh. 5.1 - A stockroom currently has 30 components of a...Ch. 5.1 - Each front tire on a particular type of vehicle is...Ch. 5.1 - Prob. 10E
Ch. 5.1 - Two different professors have just submitted final...Ch. 5.1 - Two components of a minicomputer have the...Ch. 5.1 - Prob. 13ECh. 5.1 - Suppose that you have ten lightbulbs, that the...Ch. 5.1 - Prob. 15ECh. 5.1 - Prob. 16ECh. 5.1 - An ecologist wishes to select a point inside a...Ch. 5.1 - Refer to Exercise 1 and answer the following...Ch. 5.1 - The joint pdf of pressures for right and left...Ch. 5.1 - Let X1, X2, X3, X4, X5, and X6 denote the numbers...Ch. 5.1 - Let X1, X2, and X3 be the lifetimes of components...Ch. 5.2 - An instructor has given a short quiz consisting of...Ch. 5.2 - The difference between the number of customers in...Ch. 5.2 - Six individuals, including A and B, take seats...Ch. 5.2 - A surveyor wishes to lay out a square region with...Ch. 5.2 - Prob. 26ECh. 5.2 - Annie and Alvie have agreed to meet for lunch...Ch. 5.2 - Show that if X and Y are independent rvs, then...Ch. 5.2 - Compute the correlation coefficient for X and Y...Ch. 5.2 - Prob. 30ECh. 5.2 - a. Compute the covariance between X and Y in...Ch. 5.2 - Reconsider the minicomputer component lifetimes X...Ch. 5.2 - Prob. 33ECh. 5.2 - a. Recalling the definition of 2 for a single rv...Ch. 5.2 - a. Use the rules of expected value to show that...Ch. 5.2 - Show that if Y = aX + b (a 0), then Corr(X, Y)...Ch. 5.3 - A particular brand of dishwasher soap is sold in...Ch. 5.3 - There are two traffic lights on a commuters route...Ch. 5.3 - It is known that 80% of all brand A external hard...Ch. 5.3 - A box contains ten sealed envelopes numbered 1, ....Ch. 5.3 - Let X be the number of packages being mailed by a...Ch. 5.3 - A company maintains three offices in a certain...Ch. 5.3 - Suppose the amount of liquid dispensed by a...Ch. 5.4 - Youngs modulus is a quantitative measure of...Ch. 5.4 - Refer to Exercise 46. Suppose the distribution is...Ch. 5.4 - The National Health Statistics Reports dated Oct....Ch. 5.4 - There are 40 students in an elementary statistics...Ch. 5.4 - Let X denote the courtship time for a randomly...Ch. 5.4 - The time taken by a randomly selected applicant...Ch. 5.4 - The lifetime of a certain type of battery is...Ch. 5.4 - Rockwell hardness of pins of a certain type is...Ch. 5.4 - Suppose the sediment density (g/cm) of a randomly...Ch. 5.4 - The number of parking tickets issued in a certain...Ch. 5.4 - A binary communication channel transmits a...Ch. 5.4 - Suppose the distribution of the time X (in hours)...Ch. 5.5 - A shipping company handles containers in three...Ch. 5.5 - Let X1, X2, and X3 represent the times necessary...Ch. 5.5 - Refer back to Example 5.31. Two cars with...Ch. 5.5 - Exercise 26 introduced random variables X and Y,...Ch. 5.5 - Manufacture of a certain component requires three...Ch. 5.5 - Refer to Exercise 3. a. Calculate the covariance...Ch. 5.5 - Suppose your waiting time for a bus in the morning...Ch. 5.5 - Suppose that when the pH of a certain chemical...Ch. 5.5 - If two loads are applied to a cantilever beam as...Ch. 5.5 - One piece of PVC pipe is to be inserted inside...Ch. 5.5 - Two airplanes are flying in the same direction in...Ch. 5.5 - Three different roads feed into a particular...Ch. 5.5 - Consider a random sample of size n from a...Ch. 5.5 - In Exercise 66, the weight of the beam itself...Ch. 5.5 - I have three errands to take care of in the...Ch. 5.5 - Suppose the expected tensile strength of type-A...Ch. 5.5 - In an area having sandy soil, 50 small trees of a...Ch. 5 - A restaurant serves three fixed-price dinners...Ch. 5 - In cost estimation, the total cost of a project is...Ch. 5 - Prob. 77SECh. 5 - According to the article Reliability Evaluation of...Ch. 5 - Suppose that for a certain individual, calorie...Ch. 5 - The mean weight of luggage checked by a randomly...Ch. 5 - We have seen that if E(X1) = E(X2) = =E(Xn) = ,...Ch. 5 - Suppose the proportion of rural voters in a...Ch. 5 - Let denote the true pH of a chemical compound. A...Ch. 5 - If the amount of soft drink that I consume on any...Ch. 5 - Refer to Exercise 58, and suppose that the Xis are...Ch. 5 - A student has a class that is supposed to end at...Ch. 5 - Garbage trucks entering a particular...Ch. 5 - Each customer making a particular Internet...Ch. 5 - a. Use the general formula for the variance of a...Ch. 5 - Suppose a randomly chosen individuals verbal score...Ch. 5 - Prob. 91SECh. 5 - Prob. 92SECh. 5 - Prob. 93SECh. 5 - Let A denote the percentage of one constituent in...Ch. 5 - Let X1, . . . , Xn be independent rvs with mean...Ch. 5 - A more accurate approximation to E[h(X1, . . . ,...Ch. 5 - Prob. 97SECh. 5 - Prob. 98SE
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