Questions on Algebra: Probability and statistics answered by real tutors!

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 Algebra: Probability and statistics Solvers Lessons Answers archive Quiz In Depth

 Question 61841: If 9 employees require 15 days to complete a task, how long would it take to do the same work if there were 3 additional employees? Assume that all employees are equally efficient. Click here to see answer by uma(370)

 Question 61686: Suppose that the average annual income of a defense attorney is \$150,000 with a standard deviation of \$40,000. Assume that the income distribution is normal. a) What is the probability that the average annual income of a sample of 5 defense attorneys is more than \$120,000? b) What is the probability that the average annual income of a sample of 5 defense attorneys is less than \$120,000? c) What is the probability that the average annual income of a sample of 10 defense attorneys is between \$125,000 and \$160,000? d) What is the probability that the average annual income of a sample of 15 defense attorneys is more than \$120,000? e) What is the probability that the average annual income of a sample of 50 defense attorneys is more than \$150,000? Click here to see answer by stanbon(57967)

 Question 61950: I ask for your help with the listed two exercise problems. Thank you for your help. The following information is available. 1. The sample mean is 12 for a sample of 36. The population standard deviation is 3. Use the .02 significance level Ho:u _< 10 v should be moved under the line but I do not know how to do so. H1:u >10 2. A sample of 64 observations is selected from a normal population. The sample mean is 215, and the sample standard deviation is 15. Conduct the following test of hypothesis using the .03 significance level. Ho: u >_ 220 _ should be moved just under > but I do not know how to do so. Ho: u < 220 Click here to see answer by stanbon(57967)

 Question 62115: Among U.S. households, 24% have telephone answering machines. If a telemarketing campaign involves 2,500 households, find the probability that more than 650 have answering machines Click here to see answer by stanbon(57967)

 Question 62113: Dear Sirs, I am supposed to calculate at 0.10 significance level if there is a difference between the amounts quoted. Please can you give me some guidance for the t-test? 2090 1610 1683 1247 1402 2327 1830 1367 930 1461 697 1789 1741 1621 1129 1914 1018 1956 1881 1772 1571 1375 874 1527 1579 1767 1577 1636 860 1188 Thanks very much, Gernant Click here to see answer by stanbon(57967)

 Question 62267: A study reported that in a random sampling of 100 women over the age of 35 showed that 8 of the women were married 2 or more times. In a group of 5,000 women based on the study results, how many would likely be married 2 or more times? Click here to see answer by stanbon(57967)

 Question 62488: The length of time patients must wait to see a doctor at an emergency room in a large hospital is uniformly distributed between 40 minutes and 3 hours. a) What is the probability that a patient would have to wait between 50 minutes and two hours? b) What is the probability that a patient would have to wait exactly one hour? c) What is the probability that a patient would have to wait between 60 and 90 minutes? d) What is the probability that a patient would have to wait between 120 minutes and 3 hours? e) What is the probability that a patient would have to wait between 60 and 120 minutes? Click here to see answer by stanbon(57967)

 Question 62514: please assist . There are 300 students at a college that prepare students for foreign universities. The college offers three foreign languages, English, French and German. The director of studies at the center provided the following information concerning the environment of students in these three languages. The information indicated that 100 students enrolled in English, 80 in French, 50 in german, 16 in English and French, 10 in English and German, 8 in French and German while 1 student enrolled in all the 3 languages. A student is selected at random from the college. Find the probability that the student is enrolled in a) 3 languages b) At least 2 languages c) 1 language only d) None of the languages Click here to see answer by stanbon(57967)

 Question 62542: Find the probability P(z<-0.41) using the standard normal distribution Click here to see answer by funmath(2925)

 Question 62596: I need ur help pls 1. The median income for full-time employed female americans is shown in the table below. year 1980 1988 1990 \$thousands 11.6 18.5 20.6 Assume t=0 corresponds to 1980, t=1 corresponds to 1981, etc. a. Calculate the error for the best-fit linear model for this data. b. Calculate the x-intercept for the best-fit linear model for this data. 2. What annual interest rate compounded continuously is equivalent to 4% compounded Click here to see answer by stanbon(57967)

 Question 62589: 1. The null and alternate hypotheses are: Ho: U1= U2 H1: U1=/ U2 - The /should be place across the equal sign A random sample of 15 observations from the first population revealed a sample mean of 350 and a sample standard deviation of 12. A random sample of 17 observations from the second population revealed a sample mean of 342 and a sample standard deviation of 15. At the .10 significance level, is there a difference in the population means? Use the five-step hypothesis testing procedure for the following exercises 2. Ms. Lisa Monnin is the budget director for Nexus Media, Inc. She would like to compare the daily travel expenses for the sales staff and the audit staff. She collected the following sample information Sales (\$) 131 135 146 165 136 142 Audit (\$) 130 102 129 143 149 120 139 At the .10 significance level, can she conclude that the mean daily expenses are greater for the sales staff than the audit staff? What is the p-value? 3. The management of Discount Furniture, a chain of discount furniture stores in the Northeast, designed an incentive plan for salespeople. To evaluate this innovative plan, 12 salespeople were selected at random, and their weekly incomes before and after the plan were recorded Salesperson Before After Salesperson Before After Sid Mahone Before \$320 After \$340 Carol Quick Before 290 After 285 Tom Jackson Before 421 After 475 Jack Walker Before 402 After 500 Peg Mancuso Before 625 After 631 Anita Loma Before 560 After 560 John Cuso Before 360 After 365 Carl Utz Before 431 After 431 A. S. Kushner Before 506 After 525 Fern Lawton Before 505 After 619 4. Clark Heter is an industrial engineer at Lyons Products. He would like to determine whether there are more units produced on the afternoon shift than on the day shift. A sample of 54 day-shift workers showed that the mean number of units produced was 345, with a standard deviation of 21. A sample of 60 afternoon-shift workers showed that the mean number of units produced was 351, with a standard deviation of 28 units. At the .05 significance level, is the number of units produced on the afternoon shift larger? Click here to see answer by stanbon(57967)

 Question 62656: A basket contains 6 oranges and 4 tangerines. A sample of 3 is drawn. Find the probability that 2 are tangerines and one is an orange. Click here to see answer by stanbon(57967)

 Question 61473: 1. What are the key terms in a verbal hypothesis that signify whether you are conducting a one–tailed or two-tailed test? When would you use a two population test with a large sample size at your place of employment, in your education, or in politics? Could gender be used as a variable in the creation of a test of two populations? Why or why not? When would you use a two population test with a small sample size at your place of employment, in your education, or in politics? 2. What constitutes a small sample size in a test of two populations? When testing two populations with small sample sizes, do both sample sizes have to be identical? Why or why not? 3. What are the differences among a proportion, a percentage, and a ratio? When would you use a hypothesis test for the difference in two population proportions at your place of employment, in your education, or in politics? How does a non-parametric business scenario differ from a parametric business scenario? Click here to see answer by stanbon(57967)

 Question 61244: In a recent election, 10,000 people voted, 4900 voted for Jones, 5100 voted for Smith. There was a challenge and 1,000 votes were thrown out. Assume p=P(votes for Jones)=4900/10000=.49, and that n=1000. If we randomly throw out 1000 votes, jones will need at least 4501 of the remaining 9000 to win. this means that of the 1000 thrown out, less than 400 must be "Jones" votes in order for him to win. Q: What is the probability that Jones will win under these conditions? It has to be done with the normal distribution, and I have no idea what that is...help please... Click here to see answer by stanbon(57967)

 Question 61077: Your help is appreciated please! 1. A recent article in the Wall Street Journal reported that the 30-year mortgage rate is now less than 6 percent. A sample of eight small banks in the Midwest revealed the following 30- year rates (in percent): 4.8 5.3 6.5 4.8 6.1 5.8 6.2 5.6 2. Experience raising New Jersey Red chickens revealed the mean weight of the chickens at five months is 4.35 pounds. The weights follow the normal distribution. In an effort to increase their weight, a special additive is added to the chicken feed. The subsequent weights of a sample of five-month-old chickens were (in pounds): 4.41 4.37 4.33 4.35 4.30 4.39 4.36 4.38 4.40 4.39 3. The management of White Industries is considering a new method of assembling its golf cart. The present method requires 42.3 minutes, on the average, to assemble a cart. The mean assembly time for a random sample of 24 carts, using the new method, was 40.6 minutes, and the standard deviation of the sample was 2.7 minutes. Using the .10 level of significance,for a random sample of 24 carts, using the new method, was 40.6 minutes, and the standard deviation of the sample was 2.7 minutes. Using the .10 level of significance, can we conclude that the assembly time using the new method is faster? (a) State the null hypothesis and the alternate hypothesis. (b) State the decision rule. (c) Compute the value of the test statistic. (d) What is your decision regarding H0? (e) What is the p-value? Interpret it. 4. The manufacturer of the X-15 steel-belted radial truck tire claims that the mean mileage the tire can be driven before the tread wears out is 60,000 miles.The standard deviation of the mileage is 5,000 miles. The Crosset Truck Company bought 48 tires and found that the mean mileage for their trucks is 59,500 miles.Is Crosset's experience different from that claimed by the manufacturer at the .05 significance level? Click here to see answer by stanbon(57967)

 Question 60879: can u please help me in this 5. person A tosses acoin and then person B rolls adie this is repeated independently until a head or one of the numbers 1,2,3,4 appears, at which time the game is stopped , person A wins with the head and B wins with one of the numbers 1,2,3,4 compute the probability that A wins the game Click here to see answer by stanbon(57967)

 Question 60870: The recent average starting salary for new college graduates in computer information systems is \$47,500. Assume salaries are normally distributed with a standard deviation of \$4,500. a) What is the probability of a new graduate receiving a salary between \$45,000 and \$50,000? b) What is the probability of a new graduate getting a starting salary in excess of \$55,000? c) What percent of starting salaries is no more than \$42,250? d) What is the cutoff for the bottom 5% of the salaries? e) What is the cutoff for the top 3% of the salaries? Click here to see answer by stanbon(57967)

 Question 60777: I need your assistance if anyone can help! 1. In hypothesis testing, why are verbal problem statements converted to numerical problem statements? Why is it important to identify the parameter when converting a problem statement from verbal to numerical? 2. What is the five-step process for hypothesis testing? Is the order important? Why or why not? Why do alphas differ among industries? How do ethics affect your chosen level of significance? Can you not reject and reject the null hypothesis? Why or why not? Click here to see answer by stanbon(57967)

 Question 60600: i need help in this person A tosses acoin and then person B rolls adie this is repeated independently until a head or one of the numbers 1,2,3,4 appears, at which time the game is stopped , person A wins with the head and B wins with one of the numbers 1,2,3,4 compute the probability that A wins the game Click here to see answer by stanbon(57967)

 Question 60415: Statistics are like speaking or reading a foreign language unlike any other. Thank you for your patience and support. 1. In hypothesis testing why are verbal problem statements converted to numerical problem statements? 2. Why is it important to identify the parameter when converting a problem statement from the verbal numerical? Click here to see answer by stanbon(57967)

 Question 62731: I need help to set the null and alternate hypothesis and complete the calculations. 1 2 3 77 83 80 79 91 82 87 94 86 85 88 85 78 85 80 Thank you for your help! Click here to see answer by stanbon(57967)

 Question 62749: The length of time patients must wait to see a doctor at an emergency room in a large hospital is uniformly distributed between 40 minutes and 3 hours. a) What is the probability that a patient would have to wait between 50 minutes and two hours? b) What is the probability that a patient would have to wait exactly one hour? c) What is the probability that a patient would have to wait between 60 and 90 minutes? d) What is the probability that a patient would have to wait between 120 minutes and 3 hours? e) What is the probability that a patient would have to wait between 60 and 120 minutes? Click here to see answer by Edwin McCravy(8999)

 Question 62765: A spinner has regions numbered 1 through 18. What is the probability that the spinner will stop on an even number or a multiple of 3? Click here to see answer by uma(370)

 Question 62764: Two 6-sided dice are rolled. What is the probability that the two numbers obtained differ by more than 2? Click here to see answer by jai_kos(139)

 Question 62779: A class consists of 39 women and 37 men. If a student is randomly selected, what is the probability that the student is a woman? Click here to see answer by uma(370)

 Question 62781: A fair die is rolled. What is the probability of rolling an odd number or a number less than 3? Click here to see answer by Cintchr(481)

 Question 62780: It has been observed in one country, that 55 out of every 100 births is a baby with brown eyes. In 640 births how many brown eyed babies would you expect? Click here to see answer by Cintchr(481)

 Question 62778: A bag contains 19 balls numbered 1 through 10. What is the probability that a randomly selected ball has an even number? Click here to see answer by stanbon(57967)

 Question 62770: Find the probability that when a gardner plants 20 seeds, she harvests 16 radishes given the probability that a radish seed will germinate is 0.7. Click here to see answer by stanbon(57967)

 Question 62767: What is the probability that 17 rolls of a fair die will show 7 fives? Click here to see answer by stanbon(57967)

 Question 62766: A batch consists of 12 defective coils and 88 good ones. Find the probability of getting two good coils when two coils are randomly selected if the first selection is replaced before the second is made. Click here to see answer by stanbon(57967)

 Question 62762: A certain game involves tossing 3 fair coins. It pays 29 cents for 3 heads, 12 cents for 2 heads, and 5 cents for 1 head. What is a fair price to pay to play this game? Click here to see answer by stanbon(57967)

 Question 62758: A card is drawn at random from a standard 52-card deck. Find the probability that the card is an ace or not a club. Click here to see answer by checkley71(8403)
 Question 62758: A card is drawn at random from a standard 52-card deck. Find the probability that the card is an ace or not a club. Click here to see answer by stanbon(57967)

 Question 62748: The grades of an examination are normally distributed with a mean of 75 and a standard deviation of 12. a) The students who score in the bottom 5% will be retested. What score does this represent? b) The top 10% are to receive a special award. What score must be earned to receive the award? Click here to see answer by stanbon(57967)

 Question 62746: Historical data collected at American Nationwide Mortgage revealed that 80% of all customers applying for a loan are accepted. Suppose that 50 new loan applications are selected at random. a) What is the probability that at least 42 loan applications will be accepted? b) What is the probability that more than 40 loan applications will be accepted? c) What is the probability that less than 25 loan applications will be accepted? d) What is the probability that less than 5 loan applications will be rejected? e) What is the probability that more than 30 loan applications will be accepted? Click here to see answer by stanbon(57967)

 Question 62792: For the functions f(x) = 4x + 7 and g(x) = -9x + 11, find f(g(0)). For the functions f(x) = 3x2 - 7 and g(x) = -3x2 + 4, find f(g(2)). (Do NOT put commas in large numbers.) For the functions f(x) = 3x2 - 7 and g(x) = -3x2 + 8, find g(f((-4)). (Do NOT put commas in large numbers.) For the functions f(x) = 3x2 - 8 and g(x) = -7x2 + 5, find g(f((-4)). (Do NOT put commas in large numbers.) For the functions f(x) = 3x + 6 and g(x) = -10x + 3, find g(f((4)). Click here to see answer by funmath(2925)

 Question 62811: You are dealt two cards successively ( without replacement)from a shuffled deck of 52 playing cards. Find the probability that the first card is a king and the second card is a queen. Click here to see answer by joyofmath(189)

 Question 62812: Two cards are selected without replacement from a standard deck of 52 cards. What is the probability that both cards are the same color (i.e., either both black or both red)? Click here to see answer by joyofmath(189)

 Question 62809: If A person is randomly selected, find the probability that his or her birthday is not in May. Ignore leap years. Click here to see answer by joyofmath(189)

 Question 62808: A fair die is rolled. Find the probability that the number obtained is not greater than 4. Click here to see answer by joyofmath(189)

 Question 62807: A card is drawn at random from a well-shuffled deck of 52 cards. What is the probability of drawing a face card or a 4? Click here to see answer by joyofmath(189)

 Question 62810: If you are dealt two cards successively ( with replacement of the first) from a standard 52-card deck, find the probability of getting a face card on the first card and an ace on the second. Click here to see answer by joyofmath(189)

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