Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 163033: trains A and B are traveling in the same direction on the parallel tracks. train A is traveling 80 miles per hour and train B is traveling at 90 miles per hour. Train A passed a station at 1:20am if train B passes the same station at 1:32am At what time till train B catch up with train A?
Click here to see answer by ankor@dixie-net.com(6691)   |
Question 163033: trains A and B are traveling in the same direction on the parallel tracks. train A is traveling 80 miles per hour and train B is traveling at 90 miles per hour. Train A passed a station at 1:20am if train B passes the same station at 1:32am At what time till train B catch up with train A?
Click here to see answer by jojo14344(1483)  |
Question 163129: Suppose that S and T are mutually exclusive events. Which of the following statements is true?
A) S and T cannot possibly be independent.
B) S and T may or may not be independent.
C) S and T must also be independent.
Click here to see answer by Fombitz(2113)  |
Question 163262: A certain airplane has two independent alternators to provide electrical power. The probability
that a given alternator will fail on a 1-hour flight is .02. What is the probability that (a) both will
fail? (b) Neither will fail? (c) One or the other will fail? Show all steps carefully.
Click here to see answer by stanbon(26259) |
Question 163460: assume that airplane engines operate independently of each other and that at least half of the engines on a plane must operate for the plane to continue flying. A particular airplane engine fails with a probability of 1/7. which is safer, an airplane with 2 of these engines or a airplane with 4 of these engines
Click here to see answer by Fombitz(2113) |
Question 163520: A bag contains {6} red marbles, {5} yellow marbles, and {7} green marbles. How many additional red marbles must be added to the {18} marbles alredy in the bag so that the probability of randomly drawing a red marble is {3/5}?
Click here to see answer by checkley77(7035) |
Question 163920: A group of 3 students is to be selected from a group of 12 students to take part in a class in cell biology.
a) in how many ways can this be done?
b) in how many ways can the group who will not take part be chosen?
Click here to see answer by stanbon(26259) |
Question 163995: Ten T shirt are in a drawrer. Five are white, two are blue, two are yellow, and one is red. You pick one shirt at random and replace it. After taking a shower you again randomly pick a shirt. What is the probability that you chose a white shirt both times?
Click here to see answer by stanbon(26259) |
Question 164043This question is from textbook Introduction to Statistics
: This question is from Book " Introduction to Statistics" By Ronald E. Walpole. 3rd Edition .
Q. 2 (Chapter 4 )pg 105.
A class in advanced physics is comprised of 10 juniors, 30 seniors and 10 graduate students. The final grades showed that 3 of the juniors , 10 of the seniors and 5 of the graduate students received an "A " for the course. If a student is chosen at random from this class and is found to have earned an "A",
What is the probability that he or she is a senior?
This question is from textbook Introduction to Statistics
Click here to see answer by oscargut(682)  |
Question 162966: Of the 52 people who answered yes to a quetion, 5 were male. Of the 77 that answered no to the question 11 were male. If one person is selected at random from the group, what is the probability that the person answered yes or was male.
a. 0.488
b. 0.124
c. 0.096
d. 0.527
How do I go about solving this?
Thank you for your help. I really appreciate it.
Click here to see answer by Edwin McCravy(2920) |
Question 164185: 9.56 A coin was flipped 60 times and came up heads 38 times. (a) At the .10 level of significance, is the coin biased toward heads? Show your decision rule and calculations. (b) Calculate a p-value and interpret it.
Click here to see answer by aka042(26) |
Question 164445: This question is from the book Statistics for Business and Economics. Please help me finish the problems. I can't figure it.
Business week conducted a survey of graduates from 30 top MBA programs. On the basis of the survey assume that the mean annual salary for male and female graduates 10 years after graduation is $168,000 and $117,000, respectively. Assume that standard deviation for the male graduates is $40,000, and for the female graduates it is $25,000.
What is the probability that a simple random sample of 100 male graduates will provide a sample mean more than $4000 below the population mean?
(P(X<164,000) males
n=100
U=168,000
O=40,000
Z=164,000-168,000 over 40,000 over square root of 100. (I can't figure what to do next)
Click here to see answer by themathprof(21) |
Question 164665: In establishing warranties on HDTV sets, the manufacturer wants to set the limits so that few will need repair at manufacturer expense.
On the other hand, the warranty period must be long enough to make the purchase attractive to the buyer.
For a new HDTV the mean number of months until repairs are needed is 36.84 with a standard deviation of 3.34 months.
Where should the warranty limits be set so that only 10 percent of the HDTVs need repairs at the manufacturer's expense?
Click here to see answer by themathprof(21) |
Question 164444: This question is from the book Statistics for Business and Economics. Please help me finish the problems. I can't figure it.
Business week conducted a survey of graduates from 30 top MBA programs. On the basis of the survey assume that the mean annual salary for male and female graduates 10 years after graduation is $168,000 and $117,000, respectively. Assume that standard deviation for the male graduates is $40,000, and for the female graduates it is $25,000.
What is the probability that a simple random sample of 100 male graduates will provide a sample mean more than $4000 below the population mean?
(P(X<164,000) males
n=100
U=168,000
O=40,000
Z=164,000-168,000 over 40,000 over square root of 100. (I can't figure what to do next)
Click here to see answer by themathprof(21) |
Question 164974: Can you please explain.
The probability is 1 in 4,000,000 that a single auto trip in the United States will result in a fatality. Over a lifetime, an average U.S. driver takes 50,000 trips. (a) What is the probability of a fatal accident over a lifetime? Explain your reasoning carefully. Hint: Assume independent events. Why might the assumption of independence be violated? (b) Why might a driver be tempted not to use a seat belt “just on this trip”?
Click here to see answer by checkley77(7035) |
Question 165234: Please help me with:
Answer the following questions for the function f(x)=x^8-3x^5+22
(a) What is the maximum number of zeros that the function can have?
(b) What is the maximum number of x intercepts that the function can have?
(c) What is the maximum number of turning points that the function can have?
Click here to see answer by edjones(3292)  |
Question 164964: The results shown below are mean productivity measurements (average number of assemblies completed per hour) for a random sample of workers at each of three plants. Research question: Are the mean hourly productivity levels the same for workers in these three plants? Productivity
Hourly Productivity of Assemblers in Plants
Plant Finished Units Produced Per Hour
A (9 workers) 3.6 5.1 2.8 4.6 4.7 4.1 3.4 2.9 4.5
B (6 workers) 2.7 3.1 5.0 1.9 2.2 3.2
C (10 workers) 6.8 2.5 5.4 6.7 4.6 3.9 5.4 4.9 7.1 8.4
Click here to see answer by themathprof(21) |
Question 164816: A company is taking a survey to find out
whether people like its product. Their last survey indicated
that 70% of the population like the product. Based on that,
of a sample of 58 people, find the probabilities of the following.
a. All 58 like the product.
b. From 28 to 30 (inclusive) like the product.
Click here to see answer by themathprof(21) |
Question 165502: Please help with my homework question on Interval Estimations. The book is Statistics for Business and Economics. A sample survey of 54 discount brokers showed that the mean price charged for a trade of 100 shares at $50 per share was $33.77. The survey is conducted annually. With the historical data available, assume a known population standard deviation of $15.
a. Using the sample data, what is the margin of error associated with a 95% confidence interval?
b. Develop a 95% confidence interval for the mean price charged by discount brokers for a trade of 100 shares at $50 per share.
Click here to see answer by gonzo(654) |
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