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

Algebra ->  Algebra  -> Probability-and-statistics -> Questions on Algebra: Probability and statistics answered by real tutors!      Log On

 Ad: Algebrator™ solves your algebra problems and provides step-by-step explanations! Ad: Algebra Solved!™: algebra software solves algebra homework problems with step-by-step help!

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

 Question 181061: Several years ago, the state of California launched an aggressive advertisement campaign against smoking. We've interviewed students from 17 college campuses in California and recorded for each campus the percentage of students who claimed that they had encountered at least one anti-smoking advertisement on campus in the past month. Here are those percentages: 59,58,49,53,32,27,41,52,37,51,30,25,58,60,32,37,46 construct a box-and-whisker plot for the data Click here to see answer by eperette(173)

 Question 181078: A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showed a mean purchase of \$5.29 with a standard deviation of \$3.02. For the October 26 evening showing of the same movie, for a sample of 25 purchases the mean was \$5.12 with a standard deviation of \$2.14. The means appear to be very close, but not the variances. At α = .05, is there a difference in variances? Show all steps clearly, including an illustration of the decision rule. Question out of Textbook Applied Statistics by Doane and Seward, 10.56 chapter 10. ISBN-13 978-0-07-296693-0 Click here to see answer by stanbon(57387)

 Question 181139: Conditional probability: Basic At a certain college, 47% of the students are female, and 21% of the students major in finance. Furthermore, 12% of the students both are female and major in finance. (a) What is the probability that a randomly selected finance major is female? Round your answer to 2 decimal places. (b) What is the probability that a randomly selected female student majors in finance? Round your answer to 2 decimal places. Click here to see answer by stanbon(57387)

 Question 181180: Suppose that a classroom has 4 sets of lights. The probability that one of the lights work is 0.6. Suppose that each light works independently of the others. What is the probability that none of the lights work? Round your answer to two decimals places. Click here to see answer by stanbon(57387)

 Question 181119: 4. In tests of a computer component, it is found that the mean time between failures is 530 hours. A modification is made which is supposed to increase the time between failures. Tests on a random sample of 10 modified components resulted in the following times (in hours) between failures. 518- 548- 561- 523- 536- 499- 538- 557- 528- 563 a. Determine the mean and standard deviation for the data set. (5 points) b. At the 0.01 level of significance, test the claim that for the modified components, the mean time between failures is greater than 530 hours. You may assume the time between failures is normally distributed. (5 points) Click here to see answer by stanbon(57387)

 Question 181083: The following data are the maximum temperatures (in degrees Fahrenheit) of 18 cities in the United States measured on the same day. 66,68,52,84,70,80,80,73,53,54,50,70,82,83,67,81,51,85 construct a box-and-whisker plot for the data. Click here to see answer by stanbon(57387)

 Question 181028: 1. An apple juice manufacturer develops a new juice concentrate. This new product is a) more convenient, b) higher in quality, and c) less expensive than conventional apple juice. The marketing manager needs to decide whether advertising should stress convenience, quality, or price. A pilot study is done in three small cities each promoting one of the different attributes of the new juice concentrates. Then the mean sales for each city are compared. Does the approach to advertising affect sales? That is, is there a difference in the mean sales in the three cities? An ANOVA table, shown below provides the results of the sales surveys. Test at alpha = .01. ANOVA table for one way analysis of variance: Source of D.F. Sum of Squares Mean Square F-statistic Treatment k-1 SST MST=SST/(k-1) F=MST/MSE Error n-k SSE MSE=SST/(n-k) Total n-1 SS(Total) Source of D.F. Sum of Squares Mean Square F-statistic calc Treatment 2 57,512.2 28,756 3.23 Error 58 506,983.5 8,894 Total 60 564,495.7 Use the five-step hypothesis-testing procedure. 1. State the null hypothesis: 2. State the alternate hypothesis: 3. State the decision rule (I will reject the null hypothesis if the calculated value of the test statistic, F, is (greater than, or less than, or both)_______(then fill in the value)_______. 4. State the value of the test statistic 5. What is your decision regarding the null hypothesis (accept or reject)? 6. What does this say about advertising’s affect on sales? Click here to see answer by stanbon(57387)

 Question 181215: A test of sobriety involves measuring the subjects motor skills. Twenty randomly selected sober subjects take the test and produce a mean score of 41.0 with a standard deviation of 3.7. At the 0.01 level of significance, test the claim that the true mean score for all sober subjects is equal to 35.0. You may assume that sobriety is normally distributed. Click here to see answer by stanbon(57387)

 Question 181239: Hi, can you please explain the steps (formulas) "in detail" of finding the p-value uaing a z-test, and a one tailed test and a two tailed test. Ex: z= 1764 -1750/ 70/ sqrt 150 = 2.4494 ~ 2.449 Also how do you find a critical value, do you follow the same steps? I have this example but I don't understand where 0.937 came from or what the P is and why there are the <= symbols when doing addition?: =P(Z<= -1.531) + P(Z>= 1.531) =P (Z<= -1.531)+ (1-P(Z< 1.531)) =0.063 + (1-0,937) =0.126 Thank you Click here to see answer by stanbon(57387)

 Question 181222: A manufacturer makes ball bearings that are supposed to have a mean weight of 30g. A retailer suspects that the mean weight is actually less than 30g. The mean weight for a random sample of 16 ball bearings is 29.5g with a standard deviation of 4.1g. At the 0.05 significance level, test the claim that the mean is less than 30g. You may assume the ball bearing weights are normally distributed. Use the traditional method to make your decision. Click here to see answer by stanbon(57387)

 Question 181294: Claim: The mean time between uses of a TV remote control by males during commercials equals 5.0 seconds. Find the test statistic, p-value, critical value(s), and state the final conclusion. Sample data: n = 80, x-bar = 5.25 sec. Assume that s = 2.50 sec and the significance level is a = .01. (Use p-value approach) Click here to see answer by stanbon(57387)

 Question 181383: Hi, Can you please help me solve for: Advertisers need to know which age groups are likely to see their ads. Purchasers of 120 copies of Cosmopolitan are shown by age group. (a) Make a bar chart and describe it. (b) What would be the appropriate Null and Alternate Hypotheses? (c) Calculate expected frequencies for each class. (d) Perform the chi-square test for a uniform distribution. At α = .01, does this sample contradict the assumption that readership is uniformly distributed among these six age groups? (See J. Paul Peter and Jerry C. Olson, Consumer Behavior and Marketing Strategy, 9th ed. [McGraw-Hill, 2004], p. 300.) Purchaser Age Units Sold 18~24 38 25~34 28 35~44 19 45~54 16 55~64 10 65+ 9 Total 120 Thank you, Click here to see answer by stanbon(57387)

 Question 181606: Does lovastatin (a cholesterol-lowering drug) reduce the risk of heart attack? In a Texas study,researchers gave lovastatin to 2,325 people and an inactive substitute to 2,081 people (average age 58). After 5 years, 57 of the lovastatin group had suffered a heart attack, compared with 97 for the inactive pill. (a) State the appropriate hypotheses. (b) Obtain a test statistic and p-value. Interpret the results at α = .01. (c) Is normality assured? (d) Is the difference large enough to be important? (e) What else would medical researchers need to know before prescribing this drug widely? Click here to see answer by stanbon(57387)

 Question 126817: I tried to find the answer to this question, but was totally confused. One card is selected at random from a standard 52-card deck of playing cards. Find the probability that the card selected is not a spade. Click here to see answer by jm(1)

 Question 181762: A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showed a mean purchase of \$5.29 with a standard deviation of \$3.02. For the October 26 evening showing of the same movie, for a sample of 25 purchases the mean was \$5.12 with a standard deviation of \$2.14. The means appear to be very close, but not the variances. At α = .05, is there a difference in variances? Show all steps clearly, including an illustration of the decision rule. Click here to see answer by stanbon(57387)

 Question 181873: The probability that a particular type of smoke alarm will function properly and sound an alarm in the presence of smoke is 0.8. You have 2 such alarms in your home and they operate independently. What is the probability that both sound an alarm in the presence of smoke is Click here to see answer by stanbon(57387)

 Question 181884: Hi, Can you please help me solve for this problem, it is from Doane−Seward: Applied Statistics in Business and Economics, ch. 11. My guess was to find the mean of each hospital time. Example: Hospital A 10+19+5+26+11/5 = 14.2 But I feel like there is more to the problem, am I on the right track? Problem: The waiting time (in minutes) for emergency room patients with non-life-threatening injuries was measured at four hospitals for all patients who arrived between 6:00 and 6:30 PM on a certain Wednesday. The results are shown below. Research question: Are the mean waiting times the same for emergency patients in these four hospitals? Emergency Room Waiting Time (minutes) Hospital A - 10, 19, 5, 26,11 Hospital B - 8, 25, 17, 36 Hospital C - 5, 11, 24, 16, 18, 29, 15 Hospital D - 0, 20, 9, 5, 10, 12 Thank you Click here to see answer by vleith(2825)

 Question 181886: Hi Tutors! I have a really hard problem that I'm stuck on! Please help me how to solve it! In a warehouse, accidents have been taking place at the rate of 2 every 3 months. a) What probability distribution is most likely to model the number of accidents in a 3-month period? Give reasons for your choice that are related to the problem and give any parameters for the distribution. b) Find the mean and standard deviation of the number of accidents per year and what is the percentage of months with no accidents? c) If a month is chosen at random, find the probability of at least one accident. I would really appreciate if tutors can help!! Thank you!!!! Click here to see answer by stanbon(57387)

 Question 181894: Hello, I am having some trouble with a question for my statistics homework, I hope someone would be able to help me out. I would be very grateful. Human pregnancy lengths are bell-shaped with a mean of 265 days and a standard deviation of 10 days. Use the Empirical Rule to determine the percent of women whose pregnancies are between 255 and 275 days. Using the Empirical Rule 1.About 68% of the data lie within 1 standard deviation of the mean. 2.About 95% of the data lie within 2 standard deviations of the mean. 3.About 99.7% of the data lie within 3 standard deviations of the mean. I am stuck. I am very grateful for you using your spare time to help me out . Thank you in advance. Click here to see answer by stanbon(57387)

 Question 182131: Could you explain everything that you do? Numbers 1-10 are written on cards and placed in a bag. Find each probability. 7. choosing at lease one even number when selecting 2 cards from the bag Five years after 650 high school senior graduated, 400 had a college degree and 310 were married. Half of the students with a college degree were married. 8. What is the probability that a student has a college degree or is married? Please answer me as soon as you could. Thank you for your help. Click here to see answer by stanbon(57387)

 Question 182175: This question was written by the professor who doesn't use books in his class. In a package of candies, 8 candies are green, 2 are red and 6 are white. If the first candy chosen in NOT white, what is the probability that the next one will be white (assume 1st candy was NOT put back in)? Click here to see answer by vleith(2825)

 Question 182133: Ben rolls a 1-6 number cube. Find each probability. 1.) Ben rolls a prime number or an odd number. Mr. Rodney's English class is made up of 28 students. He has 6 ESL students make up 1/5 of the remedial students and 3/5 of the advanced learners. 2.)What is the probability that a student is remedial and NOT ESL? Please explain how do you know. Please answer me as soon as you could. Thank you for your help. Click here to see answer by stanbon(57387)

 Question 182048: Hi can you please help me solve for this problem from book: Doane−Seward: Applied Statistics in Business and Economics, chapter 10: Blockbuster is testing a new policy of waiving all late fees on DVD rentals using a sample of 10 randomly chosen customers. (a) At α = .10, does the data show that the mean number of monthly rentals has increased? (b) Is the decision close? (c) Are you convinced? Customer: 1,2,3,4,5,6,7,8,9,10 No Late Fee: 14,12,14,13,10,13,12,10,13,13 Late Fee: 10,7,10,13,9,14,12,7,13,9 Thank you Click here to see answer by stanbon(57387)

 Question 182047: Hi can you please help me solve for this problem from this book: Doane−Seward: Applied Statistics in Business and Economics,chapter 10: A new drug is being tested to see if it reduces the number of migraine headaches. Assuming equal variances, at α = .025, do these samples of number of monthly migraines from eight volunteers who are taking the drug and eight who are not show a significant reduction in the mean number of monthly migraine headaches? (See Science News 165, no. 9 [February 28, 2004].) Topiramate: 3 3 2 4 3 4 3 5 Control: 3 3 5 5 7 5 5 4 Thank you Click here to see answer by stanbon(57387)

 Question 181994: Review Exercises #16. The average cost of a certain type of seed per acre is \$42. The standard deviation is \$3. Using Chebyshev's theorem, find the range in which at least 88.89% of the dte values will fall. Please help me with this problem I understand that 1-1/k2 but i don't know who to apply it... please help me. Click here to see answer by stanbon(57387)

 Question 181991: Hi Tutors! This is one of the questions I'm stuck on. Please show me how to do it. A traffic officer has a concealed radar unit that she uses to measure the speed of traffic crossing a bridge. She finds that the mean speed is 84km/h and the standard deviation is 5km/h. a) What probability distribution is most likely to model the speed of the traffic crossing the bridge? Give reasons for your choice that are related to the problem and give any parameters for the distribution. b) If the speed limit on the bridge is 90km/h, find out how many out of 200 cars she would expect to find to be breaking the limit. Thank you very very much for your help tutors!! Click here to see answer by stanbon(57387)

 Question 181962: Tutors, I am not understanding this problem please help: in Business and Economics 14.16 (a) Plot the data on U.S. general aviation shipments. (b) Describe the pattern and discuss possible causes. (c) Would a fitted trend be helpful? Explain. (d) Make a similar graph for 1992–2003 only. Would a fitted trend be helpful in making a prediction for 2004? (e) Fit a trend model of your choice to the 1992–2003 data. (f) Make a forecast for 2004, using either the fitted trend model or a judgment forecast. Why is it best to ignore earlier years in this data set? Airplanes U.S. Manufactured General Aviation Shipments, 1966–2003 Year Planes Year Planes Year Planes Year Planes 1966 15,587 1976 15,451 1986 1,495 1996 1,053 1967 13,484 1977 16,904 1987 1,085 1997 1,482 1968 13,556 1978 17,811 1988 1,143 1998 2,115 1969 12,407 1979 17,048 1989 1,535 1999 2,421 1970 7,277 1980 11,877 1990 1,134 2000 2,714 1971 7,346 1981 9,457 1991 1,021 2001 2,538 1972 9,774 1982 4,266 1992 856 2002 2,169 1973 13,646 1983 2,691 1993 870 2003 2,090 1974 14,166 1984 2,431 1994 881 1975 14,056 1985 2,029 1995 1,028 Source: U.S. Manufactured General Aviation Shipments, Statistical Databook 2003, General Aviation Manufacturers Association, Click here to see answer by stanbon(57387)

 Question 181941: Regression analysis of free throws by 29 NBA teams during the 2002-2003 season revealed the fitted regression Y = 55.2 + .73X (R2 = .874, Syx = 53.2) where Y = total free throws made and X = total free throws attempted. The observed range of X was from 1, 620 (New York Knicks) to 2,383 (Golden State Warriors) (a.) Find the expected number of free throws made for a team that shoots 2,000 free throws. (b.) Do you think that the intercept is meaningful? Hint: Make a scatter plot and let Excel fit the line (c.) Use the quick rule to make a 95 percent predicition interval for Y when X = 2,000. FGP FTP Points Fouls TrnOvr FGP 1.000 FTP - 0.039 1.000 Points 0.475 0.242 1.000 Fouls - 0.014 0.211 0.054 1.000 TrnOvr 0.276 0.028 0.033 0.340 1.000 Rbnds 0.436 0.137 0.767 - 0.032 0.202 Click here to see answer by stanbon(57387)

 Question 182417: Suppose that two cards are selected at random from a standard 52 card deck. What is the probability that both cards are less than 10 and neither of them is red? Total no of outcomes = 52 C 2 = 1326 there are 26 black and 26 red cards . After that i don't know how to proceed please help me. Thanks Click here to see answer by stanbon(57387)
 Question 182417: Suppose that two cards are selected at random from a standard 52 card deck. What is the probability that both cards are less than 10 and neither of them is red? Total no of outcomes = 52 C 2 = 1326 there are 26 black and 26 red cards . After that i don't know how to proceed please help me. Thanks Click here to see answer by scott8148(6628)
 Question 182417: Suppose that two cards are selected at random from a standard 52 card deck. What is the probability that both cards are less than 10 and neither of them is red? Total no of outcomes = 52 C 2 = 1326 there are 26 black and 26 red cards . After that i don't know how to proceed please help me. Thanks Click here to see answer by solver91311(16897)

 Question 182410: A carnival games uses plastic ducks for players to pick. If people chose one with a colored dot, they would win, those with no colored dots would not. In observing 25 games, the results were as follows: Blue was chosen 7 times or 7 out of 25 or .28 (28%) Yellow was chosen 5 times or 5 out of 25 or .20 or (20%) Red was chosen 4 times or 4 out of 25 meaning .16 or 16% and finally ducks with no dots were chosen 9 out of 25 times or 36% of time... that much I get, now the question asks...if there are 120 ducks in the game, based on the observations stated above, how many of each color of dot on the duck should there be? I have tried to multiply each percentage (given above) by the total number of ducks i.e. P(yellow) is .20, so saying 120 * .20, but that gives me 33.6 ducks...well you can't have a percentage of a duck unless it is missing parts! Can you please tell me slowly and clearly how I would solve the latter half of this problem as I think I am correct on the first part. Thanks!!! Click here to see answer by tvandenberg(45)

 Question 182462: Mr. Rodney's English class is made up of 28 students. He has 6 ESL students, 10 remedial student, and 5 advanced learners. ESL students make up 1/5 of the remedial students and 3/5 of the advanced learners. 1.) What is the probability that a student is ESL and remedial? 2.) What is the probability that a student is ESL and an advanced learner? 3.) What is the probability that a student is remedial and NOT ESL? Thank you for your help. Click here to see answer by edjones(7569)

 Question 182563: I need some help solving this problem.. USE THE NORMAL APPROXIMATION OF THE BINOMIAL PROBABILITY DISTRIBUTION TO SOLVE THE PROBLEM BELOW. DeKorte Telemarketing Inc. is considering purchasing a machine that randomly selects and automatically dials telephone numbers. It makes most of its calls during the evening, so calls to business phones are wasted. The manufacturer of the machine claims that their programming reduces the calling to business phones to 15 percent of all calls. To test this claim, the Director of Purchasing at DeKorte programmed the machine to select a sample of 150 phone numbers. What is the probability that more than 30 of the phone selected are that of a business, assuming the manufacturer’s claim is correct? Click here to see answer by stanbon(57387)