Mathematical Statistics with Applications
7th Edition
ISBN: 9781111798789
Author: Dennis O. Wackerly
Publisher: Cengage Learning
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Chapter 7.2, Problem 16E
Referring to Exercise 7.13, suppose that the effects of copper on a second species (say, species B) of fish show the variance of ln(LC50) measurements to be .8. If the population means of ln(LC50) for the two species are equal, find the
The Environmental Protection Agency is concerned with the problem of setting criteria for the amounts of certain toxic chemicals to be allowed in freshwater lakes and rivers. A common measure of toxicity for any pollutant is the concentration of the pollutant that will kill half of the test species in a given amount of time (usually 96 hours for fish species). This measure is called LC50 (lethal concentration killing 50% of the test species). In many studies, the values contained in the natural logarithm of LC50 measurements are
Studies of the effects of copper on a certain species of fish (say, species A) show the variance of ln(LC50) measurements to be around .4 with concentration measurements in milligrams per liter. If n = 10 studies on LC50 for copper are to be completed, find the probability that the sample mean of ln(LC50) will differ from the true population mean by no more than .5.
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F(x)=0.00 : x < 10.30 : 1≤x<30.40 : 3≤ x < 40.45 : 4≤ x <60.60 : 6≤ x < 121.00 : 12≤ x
a. What is the pmf of X?b. Using just the cdf, compute P(3≤ X ≤6) and P(4≤ X).
59. At a certain gas station, 40% of the customers use regular gas (A1), 35% use plus gas (A2), and 25% use premium (A3). Of those customers using regular gas, only 30% fill their tanks (event B). Of those customers using plus, 60% fill their tanks, whereas of those using premium, 50% fill their tanks.a. What is the probability that the next customer will request plus gas and fill the tank (A2 B)?b. What is the probability that the next customer fills the tank?c. If the next customer fills the tank, what is the probability that regular gas is requested? Plus? Premium?
Chapter 7 Solutions
Mathematical Statistics with Applications
Ch. 7.2 - Refer to Example 7.2. The amount of fill dispensed...Ch. 7.2 - Refer to Exercise 7.9. Assume now that the amount...Ch. 7.2 - A forester studying the effects of fertilization...Ch. 7.2 - Suppose the forester in Exercise 7.11 would like...Ch. 7.2 - The Environmental Protection Agency is concerned...Ch. 7.2 - If in Exercise 7.13 we want the sample mean to...Ch. 7.2 - Suppose that X1, X2,Xm and Y1, Y2,Yn are...Ch. 7.2 - Referring to Exercise 7.13, suppose that the...Ch. 7.2 - Applet Exercise Refer to Example 7.4. Use the...Ch. 7.2 - Applet Exercise Refer to Example 7.5. If 2 = 1 and...
Ch. 7.2 - Ammeters produced by a manufacturer are marketed...Ch. 7.2 - a If U has a 2 distribution with v df, find E(U)...Ch. 7.2 - Refer to Exercise 7.13. Suppose that n = 20...Ch. 7.2 - Prob. 22ECh. 7.2 - Applet Exercise a Use the applet Chi-Square...Ch. 7.2 - Applet Exercise Refer to Example 7.6. Suppose that...Ch. 7.2 - Applet Exercise Suppose that T is a t-distributed...Ch. 7.2 - Refer to Exercise 7.11. Suppose that in the forest...Ch. 7.2 - Applet Exercise Refer to Example 7.7. If we take...Ch. 7.2 - Applet Exercise Suppose that Y has an F...Ch. 7.2 - If Y is a random variable that has an F...Ch. 7.2 - Suppose that Z has a standard normal distribution...Ch. 7.2 - a Use Table 7, Appendix 3, to find F.01 for...Ch. 7.2 - Applet Exercise a Find t.05 for a t-distributed...Ch. 7.2 - Prob. 33ECh. 7.2 - Suppose that W1 and W2 are independent...Ch. 7.2 - Prob. 35ECh. 7.2 - Let S12 denote the sample variance for a random...Ch. 7.2 - Let Y1, Y2,,Y5 be a random sample of size 5 from a...Ch. 7.2 - Suppose that Y1, Y2,,Y5, Y6, Y,W, and U are as...Ch. 7.2 - Prob. 39ECh. 7.3 - The fracture strength of tempered glass averages...Ch. 7.3 - An anthropologist wishes to estimate the average...Ch. 7.3 - Suppose that the anthropologist of Exercise 7.43...Ch. 7.3 - Workers employed in a large service industry have...Ch. 7.3 - The acidity of soils is measured by a quantity...Ch. 7.3 - Prob. 47ECh. 7.3 - Prob. 48ECh. 7.3 - The length of time required for the periodic...Ch. 7.3 - Shear strength measurements for spot welds have...Ch. 7.3 - Refer to Exercise 7.50. If the standard deviation...Ch. 7.3 - Resistors to be used in a circuit have average...Ch. 7.3 - One-hour carbon monoxide concentrations in air...Ch. 7.3 - Unaltered bitumens, as commonly found in leadzinc...Ch. 7.3 - The downtime per day for a computing facility has...Ch. 7.3 - Prob. 56ECh. 7.3 - Twenty-five heat lamps are connected in a...Ch. 7.3 - Prob. 58ECh. 7.3 - Prob. 59ECh. 7.3 - Prob. 60ECh. 7.3 - Refer to Exercise 7.60. Suppose that n1 = n2 = n,...Ch. 7.3 - Prob. 62ECh. 7.3 - Refer to Exercise 7.62. Find the number of...Ch. 7.5 - Applet Exercise Suppose that Y has a binomial...Ch. 7.5 - Prob. 66ECh. 7.5 - Prob. 67ECh. 7.5 - Prob. 70ECh. 7.5 - Prob. 71ECh. 7.5 - A machine is shut down for repairs if a random...Ch. 7.5 - An airline finds that 5% of the persons who make...Ch. 7.5 - According to a survey conducted by the American...Ch. 7.5 - A pollster believes that 20% of the voters in a...Ch. 7.5 - a Show that the variance of Y/n, where Y has a...Ch. 7.5 - The manager of a supermarket wants to obtain...Ch. 7.5 - If the supermarket manager (Exercise 7.77) samples...Ch. 7.5 - Suppose that a random sample of 25 items is...Ch. 7.5 - Prob. 80ECh. 7.5 - Prob. 81ECh. 7.5 - Prob. 82ECh. 7.5 - Prob. 84ECh. 7.5 - Prob. 85ECh. 7.5 - Prob. 86ECh. 7.5 - Prob. 87ECh. 7 - The efficiency (in lumens per watt) of light bulbs...Ch. 7 - Refer to Exercise 7.88. What should be the mean...Ch. 7 - Prob. 90SECh. 7 - A retail dealer sells three brands of automobiles....Ch. 7 - From each of two normal populations with identical...Ch. 7 - Prob. 93SECh. 7 - Prob. 94SECh. 7 - The coefficient of variation (CV) for a sample of...Ch. 7 - Prob. 96SECh. 7 - Prob. 97SECh. 7 - Prob. 100SECh. 7 - Prob. 101SECh. 7 - Prob. 102SECh. 7 - Prob. 103SECh. 7 - Prob. 104SECh. 7 - If the probability that a person will suffer an...
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