Mathematical Statistics with Applications
7th Edition
ISBN: 9781133384380
Author: Dennis Wackerly; William Mendenhall; Richard L. Scheaffer
Publisher: Cengage Learning US
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Textbook Question
Chapter 4.5, Problem 79E
Show that the normal density with parameters μ and σ has inflection points at the values μ − σ and μ + σ. (Recall that an inflection point is a point where the curve changes direction from concave up to concave down, or vice versa, and occurs when the second derivative changes sign. Such a change in sign may occur when the second derivative equals zero.)
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Calculate the test statistic:
Calculate the P-value:
Conclusion (reject or fail to reject Ho):
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Statistics
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Chapter 4 Solutions
Mathematical Statistics with Applications
Ch. 4.2 - Prob. 1ECh. 4.2 - A box contains five keys, only one of which will...Ch. 4.2 - A Bernoulli random variable is one that assumes...Ch. 4.2 - Let Y be a binomial random variable with n = 1 and...Ch. 4.2 - Suppose that Y is a random variable that takes on...Ch. 4.2 - Consider a random variable with a geometric...Ch. 4.2 - Let Y be a binomial random variable with n=10 and...Ch. 4.2 - Prob. 8ECh. 4.2 - A random variable Y has the following distribution...Ch. 4.2 - Refer to the density function given in Exercise...
Ch. 4.2 - Suppose that Y possesses the density function...Ch. 4.2 - Prob. 12ECh. 4.2 - A supplier of kerosene has a 150-gallon tank that...Ch. 4.2 - A gas station operates two pumps, each of which...Ch. 4.2 - As a measure of intelligence, mice are timed when...Ch. 4.2 - Let Y possess a density function...Ch. 4.2 - Prob. 17ECh. 4.2 - Prob. 18ECh. 4.2 - Prob. 19ECh. 4.3 - Prob. 20ECh. 4.3 - If, as in Exercise 4.17, Y has density function...Ch. 4.3 - Prob. 22ECh. 4.3 - Prob. 23ECh. 4.3 - If Y is a continuous random variable with density...Ch. 4.3 - Prob. 25ECh. 4.3 - If Y is a continuous random variable with mean ...Ch. 4.3 - Prob. 27ECh. 4.3 - Prob. 28ECh. 4.3 - Prob. 29ECh. 4.3 - The proportion of time Y that an industrial robot...Ch. 4.3 - Prob. 31ECh. 4.3 - Weekly CPU time used by an accounting firm has...Ch. 4.3 - The pH of water samples from a specific lake is a...Ch. 4.3 - Prob. 34ECh. 4.3 - If Y is a continuous random variable such that...Ch. 4.3 - Prob. 36ECh. 4.3 - Prob. 37ECh. 4.4 - Suppose that Y has a uniform distribution over the...Ch. 4.4 - If a parachutist lands at a random point on a line...Ch. 4.4 - Suppose that three parachutists operate...Ch. 4.4 - Prob. 41ECh. 4.4 - Prob. 42ECh. 4.4 - A circle of radius r has area A = r2. If a random...Ch. 4.4 - Prob. 44ECh. 4.4 - Upon studying low bids for shipping contracts, a...Ch. 4.4 - 4.45 Upon studying low bids for shipping...Ch. 4.4 - The failure of a circuit board interrupts work...Ch. 4.4 - If a point is randomly located in an interval (a,...Ch. 4.4 - Prob. 49ECh. 4.4 - Prob. 50ECh. 4.4 - The cycle time for trucks hauling concrete to a...Ch. 4.4 - Refer to Exercise 4.51. Find the mean and variance...Ch. 4.4 - Prob. 53ECh. 4.4 - Prob. 54ECh. 4.4 - Refer to Exercise 4.54. Suppose that measurement...Ch. 4.4 - Refer to Example 4.7. Find the conditional...Ch. 4.4 - Prob. 57ECh. 4.5 - Use Table 4, Appendix 3, to find the following...Ch. 4.5 - Prob. 59ECh. 4.5 - Prob. 60ECh. 4.5 - What is the median of a normally distributed...Ch. 4.5 - If Z is a standard normal random variable, what is...Ch. 4.5 - A company that manufactures and bottles apple...Ch. 4.5 - The weekly amount of money spent on maintenance...Ch. 4.5 - In Exercise 4.64, how much should be budgeted for...Ch. 4.5 - A machining operation produces bearings with...Ch. 4.5 - Prob. 67ECh. 4.5 - Prob. 68ECh. 4.5 - Refer to Exercise 4.68. If students possessing a...Ch. 4.5 - Refer to Exercise 4.68. Suppose that three...Ch. 4.5 - Wires manufactured for use in a computer system...Ch. 4.5 - Prob. 72ECh. 4.5 - The width of bolts of fabric is normally...Ch. 4.5 - A soft-drink machine can be regulated so that it...Ch. 4.5 - The machine described in Exercise 4.75 has...Ch. 4.5 - The SAT and ACT college entrance exams are taken...Ch. 4.5 - Show that the maximum value of the normal density...Ch. 4.5 - Show that the normal density with parameters and ...Ch. 4.5 - Assume that Y is normally distributed with mean ...Ch. 4.6 - a If 0, () is defined by ()=0y1eydy, show that...Ch. 4.6 - Use the results obtained in Exercise 4.81 to prove...Ch. 4.6 - The magnitude of earthquakes recorded in a region...Ch. 4.6 - If Y has an exponential distribution and P(Y 2) =...Ch. 4.6 - Refer to Exercise 4.88. Of the next ten...Ch. 4.6 - The operator of a pumping station has observed...Ch. 4.6 - The length of time Y necessary to complete a key...Ch. 4.6 - Historical evidence indicates that times between...Ch. 4.6 - One-hour carbon monoxide concentrations in air...Ch. 4.6 - Prob. 95ECh. 4.6 - Prob. 96ECh. 4.6 - Prob. 97ECh. 4.6 - Consider the plant of Exercise 4.97. How much of...Ch. 4.6 - If 0 and is a positive integer, the...Ch. 4.6 - Prob. 100ECh. 4.6 - Applet Exercise Refer to Exercise 4.88. Suppose...Ch. 4.6 - Prob. 102ECh. 4.6 - Explosive devices used in mining operations...Ch. 4.6 - The lifetime (in hours) Y of an electronic...Ch. 4.6 - Four-week summer rainfall totals in a section of...Ch. 4.6 - The response times on an online computer terminal...Ch. 4.6 - Refer to Exercise 4.106. a. Use Tchebysheffs...Ch. 4.6 - The weekly amount of downtime Y (in hours) for an...Ch. 4.6 - If Y has a probability density function given by...Ch. 4.6 - Suppose that Y has a gamma distribution with...Ch. 4.6 - Prob. 112ECh. 4.7 - Prob. 120ECh. 4.7 - Prob. 122ECh. 4.7 - The relative humidity Y, when measured at a...Ch. 4.7 - The percentage of impurities per batch in a...Ch. 4.7 - Prob. 125ECh. 4.7 - Suppose that a random variable Y has a probability...Ch. 4.7 - Verify that if Y has a beta distribution with = ...Ch. 4.7 - Prob. 128ECh. 4.7 - During an eight-hour shift, the proportion of time...Ch. 4.7 - Prob. 130ECh. 4.7 - Errors in measuring the time of arrival of a wave...Ch. 4.7 - Prob. 132ECh. 4.7 - Prob. 133ECh. 4.7 - Prob. 134ECh. 4.7 - Prob. 135ECh. 4.9 - Suppose that the waiting time for the first...Ch. 4.9 - Prob. 137ECh. 4.9 - Example 4.16 derives the moment-generating...Ch. 4.9 - The moment-generating function of a normally...Ch. 4.9 - Identify the distributions of the random variables...Ch. 4.9 - If 1 2, derive the moment-generating function of...Ch. 4.9 - Refer to Exercises 4.141 and 4.137. Suppose that Y...Ch. 4.9 - The moment-generating function for the gamma...Ch. 4.9 - Consider a random variable Y with density function...Ch. 4.9 - A random variable Y has the density function...Ch. 4.10 - A manufacturer of tires wants to advertise a...Ch. 4.10 - A machine used to fill cereal boxes dispenses, on...Ch. 4.10 - Find P(|Y | 2) for Exercise 4.16. Compare with...Ch. 4.10 - Find P(|Y | 2) for the uniform random variable....Ch. 4.10 - Prob. 150ECh. 4.10 - Prob. 151ECh. 4.10 - Refer to Exercise 4.109. Find an interval that...Ch. 4.10 - Refer to Exercise 4.129. Find an interval for...Ch. 4.11 - A builder of houses needs to order some supplies...Ch. 4.11 - Prob. 157ECh. 4.11 - Consider the nail-firing device of Example 4.15....Ch. 4.11 - Prob. 159ECh. 4 - Prob. 160SECh. 4 - Prob. 161SECh. 4 - Prob. 162SECh. 4 - Prob. 163SECh. 4 - The length of life of oil-drilling bits depends...Ch. 4 - Prob. 165SECh. 4 - Prob. 166SECh. 4 - Prob. 167SECh. 4 - Prob. 168SECh. 4 - An argument similar to that of Exercise 4.168 can...Ch. 4 - Prob. 170SECh. 4 - Suppose that customers arrive at a checkout...Ch. 4 - Prob. 172SECh. 4 - Prob. 173SECh. 4 - Prob. 174SECh. 4 - Prob. 175SECh. 4 - If Y has an exponential distribution with mean ,...Ch. 4 - Prob. 180SECh. 4 - Prob. 181SECh. 4 - Prob. 182SECh. 4 - Prob. 183SECh. 4 - Prob. 184SECh. 4 - Prob. 185SECh. 4 - Prob. 186SECh. 4 - Refer to Exercise 4.186. Resistors used in the...Ch. 4 - Prob. 188SECh. 4 - Prob. 189SECh. 4 - Prob. 190SECh. 4 - Prob. 191SECh. 4 - The velocities of gas particles can be modeled by...Ch. 4 - Because P(YyYc)=F(y)F(c)1F(c) has the properties...Ch. 4 - Prob. 194SECh. 4 - Prob. 195SECh. 4 - Prob. 196SECh. 4 - Prob. 197SECh. 4 - Prob. 198SECh. 4 - Prob. 199SECh. 4 - Prob. 200SE
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