# 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 407872: I am having difficulties understanding this problem. can you please help. find the probability of the event: a number card (A,2,3,4,5,6,7,8,9,10) is drawn. thank you! Click here to see answer by jim_thompson5910(28595)

 Question 407809: In how many ways can 10 instructors be assigned to eight sections of a course in mathematics? Click here to see answer by jim_thompson5910(28595)

 Question 408081: 6. Each day a quality engineer selects a random sample of 100 bolts from the day’s production, measures their lengths, and computes a 95% confidence interval for the mean length of all the bolts manufactured that day. What is the probability that more than 15 of the confidence intervals constructed in the next 250 days will fail to cover the true mean? 7. On a certain day, a large number of fuses were manufactured, each rated at 15A. A sample of 75 fuses is drawn from the day’s production, and 17 of them were found to have burnout amperages greater than 15A. a. Find a 95% confidence interval for the proportion of fuses manufactured that day whose burnout amperage is greater than 15A. b. Find a 98% confidence interval for the proportion of fuses manufactured that day whose burnout amperage is greater than 15A. c. Find the sample size needed for a 95% confidence interval to specify the proportion to within ±0.05 d. Find the sample size needed for a 98% confidence interval to specify the proportion to within ±0.05 e. If a 95% confidence interval is computed each day for 200 days, what is the probability that more than 192 of the confidence intervals cover the true proportions? 8. A random sample of 400 electronic components manufactured by a certain process are tested, and 30 are found to be defective. a. Let p represent the proportion of components manufactured by this process that are defective. Find a 95% confidence interval for p. b. How many components must be sampled so that the 95% confidence interval will specify the proportion defective to within ±0.02? 9. A chemist made 8 independent measurements of the melting point of tungsten. She obtained a sample mean of 3410.14oC and a sample standard deviation of 1.018oC. a. Find a 95% confidence interval for the melting point of tungsten b. Find a 99% confidence interval for the melting point of tungsten c. If the eight measurements had been 3409.76, 3409.80, 3412.66, 3409.79, 3409.76, 3409.77, 3409.80, and 3409.78, would the confidence intervals found in parts (a) and (b) be valid? Explain. Click here to see answer by solver91311(16885)

 Question 408080: 95% of households have microwaves.If you randomly sample 3 households,what is the probability that the first two have microwaves an the last one doesn't? is this right? 3(.95+.95+.05) Click here to see answer by robertb(4012)

 Question 408051: Scripps Hospital surveyed 10 patients on each floor every day in February. Did this study use a sample or the population? Click here to see answer by robertb(4012)

 Question 408049: Given the situation described, identify the type of sampling involved. A vegan food and clothing store polls every 17th customer about the selection of desserts offered. random sampling systematic sampling convenience sampling stratified sampling cluster sampling Click here to see answer by robertb(4012)

 Question 408046: If P(A or B) = 0.8, P(A) = 0.8 and P(B) = 0.5, determine P(A and B). (Points : 3) 0.35 0.50 0.64 0.13 Click here to see answer by robertb(4012)

 Question 408019: Given the least-square regression equation Y hat=a+bX , which letter corresponds to each of the following? Regression coefficient Predictor variable Regression constant Dependent variable Click here to see answer by robertb(4012)

 Question 408045: Given that P(A) = 0.4, P(B) = 0.8, and P(A and B) = 0.10, determine P(A|B) (Points : 3) 0.08 0.32 0.25 0.125 Click here to see answer by robertb(4012)

 Question 408052: The number of baby deliveries in a small hospital was sampled over 12 hour periods. Below is the sample: 18 21 9 16 8 4 21 16 9 5 12 16 5 9 7 25 14 9 17 From this data set, compute the sample mean, median, mode and midrange. Compute the 1st quartile and 3rd and interpret their meanings. Click here to see answer by robertb(4012)

 Question 408117: A quiz consists of six multiple choice questions, each with five choices. In how many ways can a student get a perfect score on the quiz? Click here to see answer by richard1234(5390)

 Question 408132: 1. A quiz consists of six multiple choice questions, each with five choices. In how many ways can a student mark the answers to all the questions, markng all of them incorrectly? 2. Calculate the number of ways in which four paintings can be awarded first, second, third, and fourth prizes at an art competition in which a total of 30 paintings are displayed. Click here to see answer by ewatrrr(10682)
 Question 408132: 1. A quiz consists of six multiple choice questions, each with five choices. In how many ways can a student mark the answers to all the questions, markng all of them incorrectly? 2. Calculate the number of ways in which four paintings can be awarded first, second, third, and fourth prizes at an art competition in which a total of 30 paintings are displayed. Click here to see answer by richard1234(5390)

 Question 408147: ) A parent can choose from 6 types of protein, 5 vegetables and 7 desserts. If the parent serves a meal of 1 protein, 1 vegetable and 1 dessert to the family, how many different meals can be served? Click here to see answer by ewatrrr(10682)

 Question 408149: A quality control engineer tests the quality of produced computers Suppose that 5% of computers have defects and defects occur independently of each other. (a) Find the probability of exactly 3 defective computers in a shipment of 20. (b) Find the probability that the engineer has to test atleast 5 computers in order to find 2 defective ones. Click here to see answer by ewatrrr(10682)

 Question 408173: Nine guest are invited for dinner. How many ways can they be seated at a dinner table if the table is straight with seats on one side? Click here to see answer by ewatrrr(10682)

 Question 408193: The mean of a normal probability distribution is 87 and the standard deviation is 4. What is the probability of a value greater than 90? A) .2734 B) .7734 C) .2420 D) .2264 Click here to see answer by ewatrrr(10682)

 Question 408214: A card is selected from a standard deck of 52 playing cards. A standard deck of cards has 12 face cards and four Aces (Aces are not face cards). Find the probability of selecting • an even number ten or less given the card is a not a heart. • a five given the card is a face card. • an Ace, given that the card is red. Show step by step work. Give all solutions exactly in reduced fraction form. Click here to see answer by ewatrrr(10682)

 Question 408174: Classify the events as dependent or independent. Events A and B where P(A) = 0.8, P(B) = 0.3, and P(A and B) = 0.23 Click here to see answer by richard1234(5390)

 Question 408387: A bag contains a total of 30 batteries, of which six are defective. Selecting four at random, without replacement, determine the probability that none of the batteries you select are good. (Points : 2) Click here to see answer by stanbon(57342)

 Question 408470: A refrigerated case holds 24 cans of soft drinks: 6 cola, 6 root beer, 3 orange, 3 sparkling water, and 6 ginger ale. If one can is drawn at random, what is the probability of getting (a) a can of root beer (b) a can of cola or a can of ginger ale (c) a can that is neither cola, root beer, nor ginger ale Click here to see answer by ewatrrr(10682)

 Question 408469: If one card is drawn from a well-shuffled deck of 52 playing cards, what are the probabilities of getting (a) a red king (b) a black card (c) a 3, 4, 5, or 6 (d) a diamond (e) not a diamond (f) not an ace Click here to see answer by ewatrrr(10682)

 Question 408511: The value of the z-score in a hypothesis test is influenced by a variety of factors. Assuming that all other variables are held constant, explain how the value of z is influenced by each of the following: (a) Increasing the difference between sample mean and the original population mean. In terms of Z = x – u/o, keeping the o constant will have an increase in the difference between sample mean and the original population mean causes an increase in the Z score. (b) Increasing the population standard deviation. Keeping other variables like sample mean and population mean, an increase in the population standard deviation will cause a decrease in Z score. (c) Increasing the number of scores in the sample. Click here to see answer by stanbon(57342)

 Question 408527: If the population standard deviation is o = 8, how large a sample is necessary to have a standard error that is: a) less than 4 points? b) less than 2 points? c) less than 1 point? Click here to see answer by stanbon(57342)

 Question 407172: 5. Show all work. A disc jockey has 12 songs to play. Seven are slow songs, and five are fast songs. Each song is to be played only once. In how many ways can the disc jockey play the 12 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. Click here to see answer by allig(1)
 Question 407172: 5. Show all work. A disc jockey has 12 songs to play. Seven are slow songs, and five are fast songs. Each song is to be played only once. In how many ways can the disc jockey play the 12 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. Click here to see answer by lstoney(1)

 Question 408679: in a clinical trial, a drug used to reduce blood pressure caused side effects in 5% of patients who took it. 2 patients were selected at random. find the probability that both patients had side effects Click here to see answer by stanbon(57342)

 Question 408582: The theoretical probability of undesirable side effects resulting from taking Grebex is 3 in 11. If 110 people take Grebex to lower their blood pressure how many will encounter undesirable side effects? Click here to see answer by stanbon(57342)

 Question 408575: One thousand raffle tickets are sold for \$1.00 each. One grand prize of \$400 and two consolation prizes of \$100 each will be awarded. Jeremy purchases one ticket. Find his expected value. Show your work for full credit. Click here to see answer by stanbon(57342)

 Question 408775: What is the probability the person is 18 to 34 years old? What is the probability the person is 45 or older? 18-24: 29.8 25-34: 40.0 35-44: 43.4 45-54: 43.9 55-64: 32.7 65 and over: 37.8 Click here to see answer by rfer(12657)

 Question 408931: A bag contains 6 purple marbles, 7 azure marbles and 10 orange marbles. What is the chance of drawing an azure marble? If an azure marble is drawn then placed back into the bag, and a second marble is drawn, what is the probability of drawing a purple marble? Give solutions exactly in reduced fraction form, separated by a comma. Click here to see answer by ewatrrr(10682)

 Question 409103: I have the the first part to this problem, I think. The tree diagram I have drawn but have no idea if it is correct. I am completely stumped on the last 2 parts. I have read and reread the material and even looked at how some of the problems are done on here. But I am still lost on this one. PLEASE HELP! I have to turn it in this evening! Thanks... Problem: A mini license plate for a toy car must consist of a two letters followed by a one digit odd number. Each letter must be a P, Q or a R. Repetition of letters is not permitted. • Use the counting principle to determine the number of points in the sample space. • Construct a tree diagram to represent this situation. • List the sample space. • Determine the exact probability of creating a mini license plate with a Q. Give solution exactly in reduced fraction form. A) P,Q, and R = 3 ways 1 digit odd # = 5 ways 3*5 = 15 B) tree diagram 1st column P, Q, R 2nd column 1,3,5,7,9 beside each letter c) HELP! D) Help! Click here to see answer by jim_thompson5910(28595)

 Question 409168: a collection of 18 fuses contains two that are defective. if one is selected at random what is the probability that it is good? Click here to see answer by Jeef Gorrdon(26)

 Question 409141: 2 OUT OF EVERY 1000 LIGHT BULB IS DEFECTED .HOW MANY OUT OF 1000000000 IS DEFECTED" Click here to see answer by rfer(12657)

 Question 409195: I need to create a probability distribution of the number of bedrooms for the number of homes sold in Phoenx Arizona last year. I have the number of bedrooms in a spreadsheet. How would I create a probability distribution? Click here to see answer by stanbon(57342)

 Question 409310: An unprepared student makes random guesses on a 5 question true-false examination. What is the probability that she/he will answer at least one question correctly? Click here to see answer by richard1234(5390)

 Question 409362: For a normally distributed population with a mean =90 and a standard deviation =7, if Jenny has a raw score of 76, what is the z-score? Click here to see answer by ewatrrr(10682)

 Question 409442: Sherman is repairing his car. He has removed the six spark plugs. four are good and two are defective. He now selects one plug and then, without replacing it selects a second plug. 1. what is the probability that both spark plugs selected are good? 2. How is the [a] possible outcome and [b] favourable outcome calculated? 3. what is the probability that both spark plugs selected are good if we know that the first plug is good? 4. what is the probability of defective plugs? Click here to see answer by stanbon(57342)

 Question 409377: You place 14 cards marked with the digits 0–13 in a box and select one card at random. You put the card aside and select again. Write the probability as a fraction in simplest form. P(3 then 0) Click here to see answer by sudhanshu_kmr(1152)

 Question 409456: If Brian makes 65% of his free throws, what is the probability that he will make 3 out of the 5 Click here to see answer by ewatrrr(10682)