# 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 363433: If the regression equation is y^=2-0.4x, what is the value of y^ when x =-3? Click here to see answer by Fombitz(13828)

 Question 363254: how to calculate p=(-2.5820 < z < -2.0656) Click here to see answer by Fombitz(13828)

 Question 363377: In a survey of adults throughout America 75% strongly support integration.You randomly select 24 adults ,throughout America and ask each if they strongly support integration. a/ Show the the conditions for a binomial distribution are met b/ Decide whether you can use the normal distribution to approximate the binomial distribution. c/Find the Probability that 15 adults say they strongly support integration Click here to see answer by edjones(7569)

 Question 363430: In Texas 75% of all drivers wear their seat belts. A) Out of 160 drivers, what is the expected number who are wearing their seat belts? B) How many drivers will need to be observed in order to be 99.5% certain of observing more than two wearing their seat belts? Thank you in advance. Click here to see answer by robertb(4012)

 Question 363454: A random experiment has sample space S ={a, b, c}. Suppose that P[{a, c}] = 5/8 and P[{b, c}] = 7/8. Use the axioms of probability to find the probabilities of elementary events. Click here to see answer by robertb(4012)

 Question 363476: if j is chosen at random from the set { 4,5.6 }and k is chosen at random from the set { 10,11,12 }. what is the probability that the product of j and k is divisible by 5 ? Click here to see answer by robertb(4012)

 Question 363455: Show that P[A+B+C] = P[A] +P[B] +P[C] P[AB]-P[AC]-P[BC] +P[ABC] Click here to see answer by robertb(4012)

 Question 363487: What is the level of significance? a)Probability of a Type I error b) Beta error c) z-value of 1.96 d) Probability of a Type II error Click here to see answer by vasumathi(46)

 Question 363020: An automatic filling machine fills bags of potato chips with 32 ounces of chips. The population deviation is 2 ounces. Convert weights of 31 ounces and 35 ounces to z-scores and sketch the graph of the weight distribution on a bell curve with weights of 31 and 35 indicated on the graph. Click here to see answer by ewatrrr(10682)

 Question 363393: A set of 50 data values has a mean of 28 and a variance of 4. I. Find the standard score (z) for a data value = 31. II. Find the probability of a data value > 31. Click here to see answer by Fombitz(13828)

 Question 363516: a box contains several slips of paper each slip is written an odd number between 2 and 10. without looking, you draw one slip of paper. what is the sample space for the experiment? Click here to see answer by Fombitz(13828)

 Question 363429: A surgical technique is performed on seven patients. You are told there is a 70% chance of success. Find the probability that the surgery is successful for a.) exactly five patients b.) at least five patients c.) less than five patients Click here to see answer by edjones(7569)

 Question 363493: A researcher is interested in estimating the noise levels in decibels at area urban hospitals. She wants to be 98% confident that her estimate is correct. If the standard deviation is 4.74, how large a sample is needed to get the desired information to be accurate within 0.69 decibels? Show all work. Click here to see answer by stanbon(57377)

 Question 363492: Assume that the population of heights of female college students is approximately normally distributed with mean m of 67.26 inches and standard deviation s of 5.96 inches. A random sample of 78 heights is obtained. Show all work. (A) Find the mean and standard error of the x` distribution (B) Find P(x>67.50) Click here to see answer by stanbon(57377)

 Question 363541: I have the answer to this problem and I am sure I am using the correct formula, but I am not getting the correct answer of .227 The lifetime of a machine component is normally distributed with a mean of 3 and a standard deviation of .16. What is the probability that X is greater than 3.3 X ~ N(3, .16) I would like to see the process. Click here to see answer by ewatrrr(10682)
 Question 363541: I have the answer to this problem and I am sure I am using the correct formula, but I am not getting the correct answer of .227 The lifetime of a machine component is normally distributed with a mean of 3 and a standard deviation of .16. What is the probability that X is greater than 3.3 X ~ N(3, .16) I would like to see the process. Click here to see answer by stanbon(57377)

 Question 363489: The diameter of apples in a certain orchard are normally distributed with a mean of 5.5 inches and a standard deviation of 0.65 inches. Show all work. What percentage of the apple in this orchard have diameters less than 5.8 inches? What percentage of the apples in this orchard are larger than 6.3 inches? I can work the first part but I don't undersand how to get the second part. Can anyone show me what to do? z(5.8) = (5.8 -5.55)/0.65 = 0.385 P(x < 5.8) = P(z < 0.385) = ? Click here to see answer by Fombitz(13828)

 Question 363614: Hi, Cards are drawn at random and with replacement from an ordinary deck of 52 cards until a spade appears. What is the probability that at least 4 draws are necessary? Thanks! Regards, Anita Click here to see answer by edjones(7569)

 Question 363652: Solve using the substitution method. x= -2y + 4 2x - y + 8 Click here to see answer by Fombitz(13828)

 Question 363651: How many ways can the letters in the word ECOT be arranged? Click here to see answer by checkley77(12569)

 Question 363656: Hello, Can someone please help me with this problem. Given that P(A) = 0.5 and P(B) = 0.2, and P(A and B) = 0.14, determine P(B|A). (Points : 3) 0.10 0.28 0.70 0.20 Thank you, I been out of school for 15 years and I confused when it come to these type of problems I want to say it 10 but I not sure. Click here to see answer by stanbon(57377)

 Question 363556: Assume that you are taking a six-question true or false quiz. A.How many different ways are there to answer all six questions? B. How many ways are there to get no questions wrong? one question? two questions? C. If, not having studied, you simply guess at each answer what are your chances of getting two or more correct? Click here to see answer by stanbon(57377)

 Question 363695: A hat contains three chips: one red, one blue and one green. Two chips are to be selected at random with replacement. What is the probability that a green chip, then a blue chip is selected? Click here to see answer by rfer(12662)

 Question 363381: I have worked this problem and I have it until I get to the last part of how I come up with the answer. z(5.8) = (5.8 -5.55)/0.65 = 0.385 P(x < 5.8) = P(z < 0.385) = ? This is where I get stuck. The diameter of apples in a certain orchard are normally distributed with a mean of 5.5 inches and a standard deviation of 0.65 inches. Show all work. What percentage of the apple in this orchard have diameters less than 5.8 inches? What percentage of the apples in this orchard are larger than 6.3 inches? Click here to see answer by stanbon(57377)

 Question 363691: A set of data is normally distributed with a mean of 200 and a standard deviation of 50. What percentage of the scores is between 200 and 167? What would be the percentile rank for a score of 176? Click here to see answer by stanbon(57377)

 Question 363712: A student takes an exam containing 16 true or false questions. If a student randomly guesses on the entire exam, what is the expected value of the number of correct answers? Click here to see answer by stanbon(57377)
 Question 363712: A student takes an exam containing 16 true or false questions. If a student randomly guesses on the entire exam, what is the expected value of the number of correct answers? Click here to see answer by robertb(4012)

 Question 363733: Hello, can you help me with this problem, I sorry I been out of school for 15 years and I just lost with probability problems. An identification code is to consist of six letters followed by three digits. How many different codes are possible if repetition is permitted Thank you Click here to see answer by amoresroy(333)

 Question 363756: Hello Can some one tell me if my answer is right. Show all work. Mary purchased a package of 22 different plants, but she only needed 20 plants for planting. In how many ways can she select the 20 plants from the package to be planted? (Points : 3) Assuming each section is the same, and order doesnt matter. This is my answer. 22 choose 20 =22! /20! *2! =21*9/ (2*1) =189/2 =94.5 Tthank you Click here to see answer by Fombitz(13828)

 Question 363773: Hello, Can someone tell me if my answer is right. . Consider the Venn diagram below. The numbers in the regions of the circle indicate the number of items that belong to that region. Can't post the venn gram. The first circle is labeled A with 40 inside circle the overlap is 20 ab circle B is 70. Here is the questions and my answers: Determine  n(A)= 40-20=20  n(B)= 70-20=50  P(A)20/50=4/10=2/5  P(B) 50/20=5:1  P(A|B)40/70=0.571429  P(B|A)70/40=1.75 I am sorry my baby is running fever and I am a single mom with no help. Please let me know. Thank You Click here to see answer by edjones(7569)

 Question 363826: A business school claims that the average income of graduates of this school three years after graduation is \$700. a. If the claim is correct and if incomes are normally distributed with a standard deviation of \$60, what is the probability that 36 randomly selected graduates have an average income of less than \$675? b. If a random sample of 36 graduates had an average weekly income of \$675, what would you conclude about the validity of the claim? Click here to see answer by stanbon(57377)

 Question 363825: In a certain firm, the defective products will be checked to. Past experience shows that 25% of products are defective after checked. Twenty defective products are found after a long working day. a. What is the probability that all the defective products can be reworked? b. What is the probability that at least 18 defective ones can be reworked? Click here to see answer by stanbon(57377)

 Question 363823: There are 4 white balls and 8 black balls in a box. If four balls are randomly selected. The probability that exactly 2 balls are white is: a) 0.339 b) 0.406 c) 0.452 d) Other:_______ The average number of black balls obtained when four balls are randomly selected is: a) 2.333 b) 1.333 c) 2.667 d) Other : ______________ Click here to see answer by stanbon(57377)

 Question 363818: Given a level of confidence of 99% and a population standard deviation of 8, answer the following: (A) What other information is necessary to find the sample size (n)? (B) Find the Maximum Error of Estimate (E) if n = 98. Show all work. Click here to see answer by stanbon(57377)

 Question 363845: Hello Can someone please check my answer for me. Thank you so much. A disc jockey has 8 songs to play. Six are slow songs, and two are fast songs. Each song is to be played only once. In how many ways can the disc jockey play the 8 songs if  The songs can be played in any order.  The first song must be a slow song and the last song must be a slow song.  The first two songs must be fast songs. Answer: a).The songs can be played in any order slow, slow, slow, fast, slow, fast, slow, slow. = 3slow+ 1 fast; + 3 slow +1 fast = 8 b). The first song must be a slow song and the last song must be a slow 1 slow, 1fast, 1slow, 1fast, 1slow,1slow, 1slow, 1slow = 2/8 or 1/4 c) The first two songs must be fast songs. Fast, fast, slow, slow, slow, slow, slow, slow =2/8 or 1/4 Thank you, Click here to see answer by Alan3354(30993)

 Question 363731: Hello Can someone please help me with this problem. I really do not understand how to do this is there a formula that you can give me to help me. A disc jockey has 8 songs to play. Six are slow songs, and two are fast songs. Each song is to be played only once. In how many ways can the disc jockey play the 8 songs if  The songs can be played in any order.  The first song must be a slow song and the last song must be a slow song.  The first two songs must be fast songs. Thank you, Click here to see answer by Alan3354(30993)

 Question 363853: Hello, Can someone show me how to draw a tree diagram, I am really trying but I having a hard time been out of school for 15 years. Original Question: Literature Choices You decide to take a Literature course. A requirement for the course is that you must read one classic book, one nonfiction book, and one science fiction book from the list below. Classic Nonfiction Science Fiction A Farewell to Arms (F) John Adams(J) War of the Worlds (W) The Grapes of Wrath (G) Band of Brothers (B) Dune (D) Tom Sawyer (T) Moby-Dick (M)  b) Construct a tree diagram and determine the sample space. Determine the probability that  c) John Adams is selected.  d) either A Farewell to Arms or Moby-Dick is selected.  e) Moby-Dick is not selected. I have a tree diagram but I not sure if it right it has 4*2*2=16 points. Each point has three numbers in it separated by commas. (3,1,2)=Tom Sawyer, John Adams, Dune. Classic for classic I have four branches Nonfiction I have two branches Science Fiction I have two branches with the numbers 3, 2, 1. I not sure if anyone can help me with this but if you can I really would appreciate it, or atleast tell me how to draw the tree. Thank you Click here to see answer by ewatrrr(10682)

 Question 363857: How many license plates consisting of three letters (uppercase) followed by two digits are possible? Click here to see answer by amoresroy(333)

 Question 363862: 1. Consider the data set: 27, 24, 20, 15, 30, 34, 28, 25. The 25th percentile is a. 20 b. 23 c. 25 d. 27 2. Among 25 articles, nine are defective, six having only minor defects and three having major defects. Detemine the probability that an article selected at random has major defects given that it has defects: a. 0.15 b. 0.18 c. 1/3 d. Ό 3. I toss a dice and you toss a dice. What is the probability of having same number: a. 1/6 b. 1/36 c. 1/12 d. 1/3 Click here to see answer by stanbon(57377)

 Question 363870: A 95% confidence interval estimate for a population mean was computed to be (28.7, 40.9). Determine the mean of the sample, which was used to determine the interval estimate (show all work). Click here to see answer by stanbon(57377)

 Question 363894: Two random sample of size n1 = 9 and n2 = 16 from two independent populations having normal distribution provide the means and Standard deviations as follows: X1 = 64, X2 = 52, s1=6 , s2 =5 Find 95% confidence interval for ΅1  ΅2 assuming ΅1 = ΅2. Click here to see answer by stanbon(57377)

 Question 363940: Hello, I worked this problem but I not sure if it right I think that it might be, can you please check it for me, Thank you very much for your help. Given that P(A) = 0.4, P(B) = 0.5, and P(A and B) = 0.10, determine P(A|B) (Points : 3) 0.28 0.20 0.25 0.09 Answer is : .25 Click here to see answer by SadieKhan(31)

 Question 363905: * Items are inspected for flaws by two quality inspectors. If a flaw is present, it will be detected by the first inspector with probability 0.90, and by the second inspector with probability 0.70. Assume the innspectors function independently. a. If an item has a flaw, what is the probability that it will be found by both inspectors? b. Assume that the second inspector examines only those items that have been passed by the first inspector. If an item has a flaw, what is the probability that the second inspector will find it? Click here to see answer by SadieKhan(31)

 Question 363910: Two independent groups, each of 10 children, were tested in general knowledge. Test scores were as follows: Group A 7 7 6 7 9 6 8 6 6 10 Group B 6 6 4 7 8 6 6 5 6 8 Is the difference between mean scores of the two groups significant? Use 5% level of significance. Click here to see answer by SadieKhan(31)

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