# 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 272695: The faces of a cube are numbered from 1 to 6.What is the probability of not rolling a 5 on a single toss of this cube? a 1/5 b 1/6 c 5/6 d 4/5 Click here to see answer by stanbon(57424)

 Question 272538: A random sample of 420 new hybrid vehicles showed that 105 required repairs within the first warranty year. Wha is the probability that a new hybrid vehicle will need repairs within the first warranty year? Click here to see answer by stanbon(57424)

 Question 272788: Categorize each mathematical statement as either always true or never true. Select your answer from the pull-down list. 2x + 1 = 2x – 1 =not true 1 – 1/x = 1 + x =Always True (a – b)c = ac – bc =not true Are my answers correct and if not why? Click here to see answer by stanbon(57424)

 Question 272912: Vocabulary; The ? Of an event is never grater than 1 and never less than 0. Click here to see answer by richwmiller(9143)

 Question 272951: A postal carrier distributes letters, ads, and magazines. The break donw of deliveries is: Delivered to / Letter / Ads / Magazines Homes /775 / 880 /270 Business /485 /417 /180 Questions A What is the probability that it was an ad? B What is the probability that it was and ad delivered to a home? C What is the probability that it was an add or it was delivered to a home? Click here to see answer by stanbon(57424)

 Question 272963: Of 1937 people who came into a blod bank to give blood, 679 had high blood pressure. Estimate the probability that the next person who comes in will also have high blood pressure. Click here to see answer by stanbon(57424)

 Question 273001: The deck is 2 regular decks of cards plus 4 jokers for a total of 108 cards. and with out replacement What is the probability of drawing two sevens and two queens in succession?? Click here to see answer by stanbon(57424)

 Question 273077: A binomial distribution has n=1580 and p=0.798 A Find the mean of this distribution to the nearest tenth. B Find the variance and standard deviation of this distribution to the nearest hundredth C Find the minimum and maximum usual values of U +- 2 r Click here to see answer by stanbon(57424)

 Question 273038: 1. Find the critical value zc necessary to form a confidence interval at 97% level of confidence Click here to see answer by stanbon(57424)

 Question 273094: A Teaching Assistant develops a multiple choice test that consists of 10 questions. Each question consists of four possible answers, with one answer being correct. If a student has no idea regarding the correct answers to the questions, what is the likelihood of obtaining exactly, 1,2,3,4,5,6,7,8,9,or 10 correct answers Click here to see answer by stanbon(57424)

 Question 273154: Researchers want to estimate the mean weight of all chipmunks living in Albuquerque, NM. Using the population standard deviation of 1.4 ounces as in Question #5, find the sample size required if we want our margin of error to be less than 0.25 ounces with 95% confidence. Click here to see answer by stanbon(57424)

 Question 273153: The weights of adult chipmunks vary according to a normal distribution with standard deviation 1.4 ounces. Researchers suspect that the mean weights of populations of chipmunks depend on where they live. A team of biologists caught, weighed, and released 15 chipmunks in Rocky Mountain National Park, and the mean weight for this sample was 8.2 oz. Which of the following is a 96% confidence interval for the true mean weight of chipmunks in the park? Click here to see answer by stanbon(57424)

 Question 273152: A business that repairs major appliances charges a flat fee and hourly amount plus the cost of any needed parts. They know that the time required to repair an appliance has a standard deviation of 0.25 hours. The mean depends on the type of appliance. To estimate the true mean time required to repair side-by-side refrigerators, they will take a random sample of 60 refrigerator repairs. If they want a 99% confidence interval, what will the margin of error in their estimate be? Your answer should be a number rounded to TWO decimal places Click here to see answer by stanbon(57424)

 Question 273187: 1. The lifetime X of an electronic component has probability density function f(x) = c=x2 for x > 10, and f(x) = 0 otherwise. (a) Determine the value of c. (b) Find the distribution function F(x) of X. (c) Find E(X) if it exists. (d) If an electronic device consists of 6 such components which operate independently, what is the probability that at least 2 will still be working after 15 time units? Does E(x) exist? I need help with d) Click here to see answer by stanbon(57424)

 Question 273125: The number of golf balls ordered by customers of a pro shop has the following probability distribution: x 3 / 6 / 9 / 12 / 15 / ______________________________________ P(X) 0.27 / 0.17 /0.33 / 0.12 / 0.11 / I know the mean is 7.89 and the standard deviation is 3.88 u=sum(x times P(x)) divided by P(P(x)) I'm not sure what is the process of this question Find the probability of six or more golf balls being ordered? Click here to see answer by stanbon(57424)

 Question 273197: Three standard number cubes are tossed. What is the probability that the sum of the numbers on the tops of the cubes will be 17 or greater? Click here to see answer by stanbon(57424)

 Question 273221: At a certain university, the average cost of books per student was \$330 per student last semester. In a sample of 50 students this semester, their average cost was \$355 with a standard deviation of \$85. The Dean of Students believes that the costs are greater this semester. What is the test value for this hypothesis? Click here to see answer by stanbon(57424)

 Question 273194: What is the probability that 12 couples having babies will all have girls? Thank you so so much! Click here to see answer by stanbon(57424)

 Question 273271: An industrial firm allows a discount on any invoice that is paid within 30 days. it is known that 12% of all invoices recieve the discount. In a company audit 9 invoices are randomlu selected independent of each other. Let x be the number of invoices among the selected 9 that receive the discount. a- find the probability that exactly 3 invoices amond these 9 receive the discount. b- find the probability that at least one of the invoices receives a discount. c- find the mean and standard deviation of x. Click here to see answer by stanbon(57424)

 Question 273117: The ratio of men to women at a certain company is 3 to 5 . How many employees does the company have if there are 75 female employees? Click here to see answer by ankor@dixie-net.com(15667)

 Question 273346: Suppose the probability of A is .3, the Probability of B is .45 and the probability of P(A or B)=.7; what is the probability of A and B, that is P(A and B)? Click here to see answer by jim_thompson5910(28598)

 Question 260477: In a battleground state, 36% of all voters are Republicans. Assuming that there are only two parties - Democrat and Republican, if two voters are randomly selected for a telephone survey, what is the probability that they are both Republicans? Round your answer to 4 decimal places Click here to see answer by kristip14(1)

 Question 273580: Mr. Slayer is a buyer for an electronics store. he received a shipment of 5 DVD players in which one is defective. He randomly chose 1 of the DVD players to test. Suppose the defective player is one of the three that Mr. Slayer tested. What is the probability that the last one tested was the defective one? Click here to see answer by Theo(3472)

 Question 273698: If the paired differences are normal in a test of mean differences, the distribution used for testing is the Click here to see answer by stanbon(57424)

 Question 273687: You ask a neighbor to water a sickly plant while you are on vacation. Without water the plant will die with probability 0.85. With water it will die with probability 0.55. You are 88 % certain the neighbor will remember to water the plant. You come back from the vacation and the plant is dead. What is the probability that the plant died because neighbor forgot to water it? Click here to see answer by jim_thompson5910(28598)

 Question 273684: A telemarketer calls people and tries to sell them a subscription to a daily newspaper. On 16% of her calls, there is no answer or the line is busy. She sells subscriptions to 10% of the remaining calls. For what proportion of calls does she make a sale? Click here to see answer by Alan3354(30993)

 Question 273759: I was wondering if this is right :) 4. When a pizza restaurant’s delivery process is operating effectively, pizzas are delivered in an average of 45 minutes with a standard deviation of 6 minutes. To monitor its delivery process, the restaurant randomly selects five pizzas each night and records their delivery times. For the sake of the argument, assume that the population of all delivery times on a given evening is normally distributed with a mean of µ = 45 minutes and a standard deviation of δ = 6 minutes. z= X - mean/standard deviation = 5-45/6=-6.66 The area between z=0 and z=-6.66-= how do i find the area?? do I double 3? Click here to see answer by stanbon(57424)

 Question 273723: A sample of 10 observations is selected from a normal population for which the population standard deviation is known to be 5. The sample mean is 19 (a) The standard error of the mean is Click here to see answer by stanbon(57424)

 Question 273666: Dana has decided to apply to 7 colleges and wants to visit them over spring break. In how many ways can Dana choose the 4 colleges to visit? Click here to see answer by stanbon(57424)

 Question 274006: Exercise 7 Bob Nale is the owner of Nales Texaco GasTown. Bob would like to estimate the mean number of gallons of gasoline sold to his customers. Assume the number of gallons sold follows the normal distribution with a standard deviation of 3 gallons. From his records, he selects a random sample of 58 sales and finds the mean number of gallons sold is 8.51. (Round your answers to 2 decimal places.) (a) The point estimate of the population mean is ? (b) The 99 percent confidence interval for the population mean is and ? Click here to see answer by stanbon(57424)

 Question 274080: I am working with a data set that is normally distributed, with a mean of 200 and a standard deviation of 47. I need to determine the value of x from the following information: a) 60% fo the values are greater than x b) x is less than 17% of the values c) 22% of the values are less than x d) x is greater than 55% of the values. Click here to see answer by stanbon(57424)

 Question 274141: A tea set has 4 cups and saucers.Two of which are of same color and the other two are of different color.If the cups are placed randomly on the saucers.What is the probability that no cup is on a saucer of same color Click here to see answer by Edwin McCravy(8924)

 Question 274119: three cards are drawn in succession from a deck without replacement. Find the probability distribution for the number of spades. Click here to see answer by stanbon(57424)

 Question 274113: the owner of a professional basketball team claims that the mean attendance at games is over 18,000 and therefore the team needs a new areana. Determine wheather the hypothesis test claim is left-tailed , right tailed, or two tailed Click here to see answer by stanbon(57424)

 Question 274303: 1.6x-2.8y + 9.8= 0 need x and y intercept Click here to see answer by stanbon(57424)
 Question 274303: 1.6x-2.8y + 9.8= 0 need x and y intercept Click here to see answer by checkley77(12569)

 Question 274341: You draw 2 cards from a well-shuffled deck of 52 cards. After you draw the first card, you do not replace it in the deck. The probability of drawing the ace of spades on your first draw is . What is the probability of P(get queen of hearts on second draw | get ace of spades on first draw)? Click here to see answer by edjones(7569)

 Question 274396: If the letters A, B, C, D, E, and F are to be used in a five-letter code, how many different codes are possible if repetitions ARE PERMITTED? Click here to see answer by stanbon(57424)

 Question 274425: Your home's security system has a component which is 90% reliable with a back-up component that is 70% reliable. Assume that the reliabilities of the two components are independent. If someone burglarizes your home, what is the probability that (a) both components fail? (b) at least one component functions properly? Click here to see answer by stanbon(57424)

 Question 274424: Suppose that each question of a three-question multiple choice quiz has 5 choices. If you randomly choose an answer to each of the questions, what is the probability that none of the answers are correct? Click here to see answer by stanbon(57424)

 Question 274423: . A couple plans to have two children. Assume that on any given birth, having a boy and having a girl are equally likely. (a) What is the probability that exactly one of the children is a boy? (b) What is the probability that at least one of the children is a boy? Click here to see answer by stanbon(57424)

 Question 274417: Two dates are selected at random from the 365 days of the year. Determine the number of possible outcomes if the dates are selected (a) with replacement (i.e. we CAN pick the same date twice). (b) without replacement (i.e. we CANNOT pick the same date twice). Bonus: If I randomly pick 2 people off of the street, what is the probability that they have the same birthday? (I mean the day, not the year). Click here to see answer by stanbon(57424)

 Question 274477: The average mpg usage for a 2004 Ford Expedition 2WD for a sample of 10 tanks of gas was 17.0 with a standard deviation of 0.8. For a Ford Explorer 2WD, the average mpg usage for a sample of 10 tanks of gas was 18.5 with a standard deviation of 1.0. (a) Assuming equal variances, at α = .01, is the true mean mpg lower for the Ford Expedition? (b) Calculate the p-value using Excel. Click here to see answer by stanbon(57424)

 Question 274529: In a sample of 10 discs, it is known that 2 are defective. Three discs are selected at random and without replacement from this sample. What is the probability that: a) all three are defective b) none is defective c) two only are defective can you please give me the answer with the solution? thanks Click here to see answer by Theo(3472)

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