# 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 263399: 2) “µ = 17” is an appropriate null hypothesis. A. True B. False Click here to see answer by stanbon(57347)

 Question 263395: 1) The value that separates a rejection region from a non-rejection region is called the test statistic. A. True B. False Click here to see answer by stanbon(57347)

 Question 263379: Mean: 1.31 Standard deviation: 0.04 random Sample: 16 What is the probablity that the sample is between 1.28 and 1.32 Click here to see answer by stanbon(57347)

 Question 250029: 25. Suppose 2 cards are drawn without replacement from an ordinary deck of 52. Find the probabilities of the following results. a. One is a face card and the other is not. b. At most one is a queen. pick face card 4C2 = 12 ways 2 cards w/o restriction 52C2 P (2 cards) = 12/22100 = 6/11050 = 1841.666???? Click here to see answer by whistler68(1)

 Question 263461: An automobile manufacturer produces 7 models, each available in 6 different exterior colors, with 4 different upholstery fabrics and 5 interior colors. How many varieties of automobile are available? Click here to see answer by checkley77(12569)

 Question 263548: HI! I saw this on a webpage: Tutorial on the Use of Significant Figures, page 7 -------------------------------------------------------------------------------- General guidelines for using calculators When using a calculator, if you work the entirety of a long calculation without writing down any intermediate results, you may not be able to tell if an error is made. Further, even if you realize that one has occurred, you may not be able to tell where the error is. In a long calculation involving mixed operations, carry as many digits as possible through the entire set of calculations and then round the final result appropriately. For example, (5.00 / 1.235) + 3.000 + (6.35 / 4.0)=4.04858... + 3.000 + 1.5875=8.630829... The first division should result in 3 significant figures. The last division should result in 2 significant figures. The three numbers added together should result in a number that is rounded off to the last common significant digit occurring furthest to the right; in this case, the final result should be rounded with 1 digit after the decimal. Thus, the correct rounded final result should be 8.6. This final result has been limited by the accuracy in the last division. Warning: carrying all digits through to the final result before rounding is critical for many mathematical operations in statistics. Rounding intermediate results when calculating sums of squares can seriously compromise the accuracy of the result. This is on a chemistry webpage dealing with significant figures. What do the two sentences after the word warning mean exactly? I don't understand this. Click here to see answer by stanbon(57347)

 Question 263647: The University of Metropolis requires its students to pass an examination in college-level mathematics before they can graduate. The students are given three chances to pass the exam; 61% pass it on their first attempt, 63% of those that take it a second time pass it then, and 42% of those that take it a third time pass it then. What percent of the students are not allowed to graduate because of their performance on the exam? (Round the answer to the nearest whole number.) Click here to see answer by rfer(12660)
 Question 263647: The University of Metropolis requires its students to pass an examination in college-level mathematics before they can graduate. The students are given three chances to pass the exam; 61% pass it on their first attempt, 63% of those that take it a second time pass it then, and 42% of those that take it a third time pass it then. What percent of the students are not allowed to graduate because of their performance on the exam? (Round the answer to the nearest whole number.) Click here to see answer by MathTherapy(1424)

 Question 263636: The University of Metropolis requires its students to pass an examination in college-level mathematics before they can graduate. The students are given three chances to pass the exam; 61% pass it on their first attempt, 63% of those that take it a second time pass it then, and 42% of those that take it a third time pass it then. What percent of the students are not allowed to graduate because of their performance on the exam? (Round the answer to the nearest whole number.) Click here to see answer by stanbon(57347)

 Question 263759: Art works in a small retail store that sells widgets. Market research shows that red is, by far, the most popular color of widget, and that 38% of customers purchase red widgets. If Art selects 5 random customers and records the color of widget purchased, what is the probability that at least one of those customers purchased a red widget? What I did was take .38 x .38= .1444 and then add .1444 to .38. I got .5244, then multiplied that by .38. I then added this new number to .38 and got .579272, I kept doing this until I got 0.6080468. I don't know if this is right so I need help. Click here to see answer by stanbon(57347)

 Question 263800: A box contains some green marbles and exactly four red marbles. The probability of selecting a red marble is x%. If the number of green marbles is doubled, the probability of selecting one of the four red marbles from the box is (x – 15)%. How many green marbles are in the box before the number of green marbles is doubled? Click here to see answer by stanbon(57347)

 Question 263705: the orange county department of public health tests water for contamination due to the presence of E.coli bacteria. To reduce laboratory costs, water samples from six public swimming areas are combined for one test, and further testing is done only if the combined sample fails. Based on past results, there is a 2% chance of finding E.coli bacteria in a public swimming area. Find tthe probbality that a combined sample from six public swimming area will reveal the presence of E.coli bacteria. I have tried it so far. Sample space=6 (2/100)*6= .12 I am not sure if its right, please any help? Click here to see answer by stanbon(57347)

 Question 263816: What is the probability that the square root of a randomly selected two-digit whole number is less than eight? Express your answer as a common fraction. Click here to see answer by Greenfinch(383)

 Question 263823: A manufacturer of tire found out that 2 % of his production was defective. If you have just bought a new car with 4 of those tires , what is the probability that one of these tires is defective. thanks for your help Click here to see answer by Theo(3464)

 Question 263875: 7) In a test of the equality of two means, the variable of interest is the difference between the values of the observations, rather than the observations. A. True B. False Click here to see answer by stanbon(57347)

 Question 263874: In a bumper test, three types of autos were deliberately crashed into a barrier at 5 mph, and the resulting damage (in dollars) was estimated. Five test vehicles of each type were crashed, with the results shown below. Research question: Are the mean crash damages the same for the three vehicles? Goliath Varmint Weasel 1,600 1,290 1,090 760 1,400 2,100 880 1,390 1,830 1,950 1,850 1,250 1,220 950 1,920 Click here to see answer by stanbon(57347)

 Question 263979: A random sample of 100 patients taken at a community hospital shows the mean time for a patient to see a physician is 25 minutes with a standard deviation of 6 minutes. a What proportion of patients will be seen by an ER physician in less than 20 minutes? b What proportion of patients will be seen by an ER physician between 25 and 30 minutes? Completing in Excel and I want to make sure I am on the right track. Click here to see answer by stanbon(57347)

 Question 264003: In a certain class, 40% of the students are seniors, 15% are failing, and 10% are seniors who are failing. What is the probability that a randomly choosen student is failing? Click here to see answer by stanbon(57347)

 Question 263862: 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 witha standard deviation of \$2.14. The mean 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. (Data are from a project by statistics students Kim Dyer, Amy Pease, and Lyndsey Smith.) Click here to see answer by stanbon(57347)

 Question 263860: To test the hypothesis that students who finish an exam first get better grades, Professor Hardtack kept track of the order in which papers were handed in. The first 25 papers handed in showed a mean score of 77.1 with a standard deviation of 19.6, while the last 24 papers handed in showed a mean score of 69.3 with a standard deviation of 24.9. Is this a significant difference a α = .05? a)State the hypothesis for a right-tailed test. b)Obtain a test statistic and p-value assuming equal variances. Interpret these results. c)Is the difference in mean scores large enough to be important? d)Is it reasonable to assume equal variances? e)Carry out a formal test for equal variances at α = .05, showing all steps clearly. Click here to see answer by stanbon(57347)

 Question 263850: Does Iovastatin (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 appropiate hypothesis. 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? (Data are from Science News 153 [May 30, 1998], p, 343. Click here to see answer by stanbon(57347)

 Question 263842: In Dallas, some fire trucks were painted yellow (instead of red) to heighten their visibility. During a test period, the fleet of red fire trucks made 153,348 runs and had 20 accidents, while the fleet of yellow fire trucks made 135,035 runs and had 4 accidents. at α = .01, did the yellow fire trucks have a significantly lower accident rate? a)state the hypothesis. b)State the decision rule and sketch it. c)find the sample proportions and z test statistic. d)Make a decision. e)Find the p-value and interpret it. f)If statistically significant, do you think the difference is large enough to be important? if so, to whom, and why? g)Is the normality assumption fulfilled? Explain. Click here to see answer by stanbon(57347)

 Question 263817: A poker hand (5 cards) is drawn from an ordinary deck of 52 cards. Find the probability of each event, showing your reasoning. Click here to see answer by stanbon(57347)

 Question 264049: Suppose you randomly choose a number between 1 and 20.What are the odds in favor of choosing a prime number? Click here to see answer by jim_thompson5910(28595)
 Question 264049: Suppose you randomly choose a number between 1 and 20.What are the odds in favor of choosing a prime number? Click here to see answer by drk(1908)

 Question 264091: I need to identify the variable and write an equation that describes the situation below. If 9% of the members buy tickets then we 252 to this group? Click here to see answer by stanbon(57347)

 Question 263819: J.D. Power and Associates says that 60 percent of car buyers now use the Internet for research and price comparisons. (a) Find the probability that in a sample of 8 car buyers, all 8 will use the Internet; (b) at least 5; (c) more than 4. (d) Find the mean and standard deviation of the probability distribution. (e) Sketch the PDF (using Excel or Appendix A) and describe its appearance (e.g., skewness). (Data are from J. Paul Peter and Jerry C. Olson, Consumer Behavior and Marketing Strategy, 7th ed. [McGraw-Hill/Irwin, 2005], p. 188.) Click here to see answer by stanbon(57347)

 Question 264403: A group of 10 people consists of 5 men and 5 women. A committee of 4 is chosen from this group. What is the probability that one or more of the committee members is a man? Click here to see answer by stanbon(57347)
 Question 264403: A group of 10 people consists of 5 men and 5 women. A committee of 4 is chosen from this group. What is the probability that one or more of the committee members is a man? Click here to see answer by drk(1908)

 Question 264375: A lottery ticket has a color: Red or Blue followed by one number among 1, 2 and 7. (a) Specify the sample space for this experiment by listing all possible outcomes. (b) Let A be the event that the number of the ticket is an odd number, and B be the event that the color of the ticket is blue. Specify the three events A, B and (A and B) by listing all the outcomes in each event. (c) Find the probabilities P(A), P(B) and P(A and B). (d) Find the probability P(A or B) . Click here to see answer by stanbon(57347)

 Question 264417: The time needed to complete the final examination of MGSC 301 is normally distributed with a mean of 120 minutes and a standard deviation of 12 minutes. a. What is the probability that a student will finish the examination in two hours or more? b. What is the probability that a student will finish the examination in more than 100 minutes but less than 150 minutes? c. What is the probability that a student will finish the examination in more than 140 minutes? Click here to see answer by stanbon(57347)

 Question 264464: 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 vksarvepalli(154)

 Question 264481: A menu offers a choice of 3 salads, 8 main dishes, and 5 desserts. How many different meals consisting of one salad, one main dish, and one dessert are possible? Click here to see answer by stanbon(57347)

 Question 264492: Recall that in the 2000 election, 48.4% of votes were cast for Al Gore. If we take a random sample of 50 voters from that election, and we want to compute the probability that more than 52% of them voted for Gore, i.e., P(p hat>0.52), which of the following standard normal probabilities equals this probability? A)P(Z > 0.51) B)P(Z > 0.036) C)P(Z > 0.01) D)P(Z > 0.52) Click here to see answer by stanbon(57347)

 Question 264435: Hello, First off, thank you for your help. My mind is at a total loss; it has been awhile since I took statistics. Preceding the question, you need to know what the teacher wants. Three companies are accussed of stealing money from a parking meter. She wants us to find the mean median and mode of the numbers given. We are given the total income or revenue the city receives from each company. Here are the numbers for company 1 (brinks) 166,410. Company two (cdc) collected 81199. company three collected collected 74171. Again, the mean median and mode need to be found. I believe these are not mutually exclusive events. Please help. Thanks for your time Click here to see answer by stanbon(57347)

 Question 264518: A firm is studying the production times for two production methods. The firm is satisfied with production method A and is prepared to continue using it if the mean delivery time is the same as or less than for production method B. However, if the firm finds that the mean delivery time for method B is less than that for method A, it will begin using method B. a. What are the null and alternative hypotheses? Assume that independent samples show the following delivery time characteristics for the two production methods. Method A Method B b. With  = .02, what is your conclusion for the hypotheses from part a? (Show your work.) c. What action do you recommend regarding selection of a production method? Click here to see answer by stanbon(57347)

 Question 264537: How do you estimate the probability of success if a single piece of candy is drawn from a bag at random? Click here to see answer by Alan3354(30993)

 Question 264516: A new car is designed to run a mean of at least 50 000 kilometres before its first tune-up. Tests with 30 cars show a sample mean of 49 500 kilometres and a sample standard deviation of 1000 kilometres. a. Develop the null and alternative hypotheses most appropriate for testing the claim that the new car can run at least 50 000 kilometres before its first tune-up. b. Using a .05 level of significance, test whether or not there is sufficient evidence to reject the claim of a mean of at least 50 000 kilometres. c. What is the p-value. Click here to see answer by stanbon(57347)

 Question 264499: The number of years of education of self-employed individuals in the U.S. has a population mean of 13.6 years and a population standard deviation of 3.0 years. If we survey a random sample of 100 self-employed people to determine the average number of years of education for the sample, what is the mean and standard deviation of the sampling distribution of x-bar (the sample mean)? Enter your answers below to one decimal place Click here to see answer by bckpck(1)

 Question 264581: A multiple choice test has 20 questions with each having 4 possible answers with one correct. Assume a student randomly guesses the answer to every question a. What is the probability of getting exactly 9 correct answers? b. What is the probability of getting less than 9 correct answers? Click here to see answer by stanbon(57347)

 Question 264613: The random Variable X has a binomial distribution with n=10 and p= 0.5. Determine the probabilities (a) P(X=5) (b) P(X ≤ 2) (c) P(X ≥ 9) (d) P( 3 ≤ X < 5) Click here to see answer by stanbon(57347)

 Question 264625: If you roll six ordinary six-sided dice and add the two numbers that appear, how many different sums are possible? Why? Click here to see answer by checkley77(12569)

 Question 264622: How many ways can a committee of 7 be chosen from 20 people? I know you use 20 C 7 and that the answer is 77520, but I do not understand HOW to get the answer, can anyone do it step by step? Click here to see answer by checkley77(12569)

 Question 264726: The number of years of education of self-employed individuals in the U.S. has a population mean of 13.6 years and a population standard deviation of 3.0 years. If we survey a random sample of 100 self-employed people to determine the average number of years of education for the sample, what is the mean and standard deviation of the sampling distribution of x-bar (the sample mean)? Enter your answers below to one decimal place Click here to see answer by stanbon(57347)

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