# 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 439237: In a binomial dist b( 9, 1/3 ), the SD is equal to Click here to see answer by stanbon(57984)

 Question 439309: Please help! This is the last question of the last week of this class. Thank you for your help. John Isaac, Inc., a designer and installer of industrial signs, employs 60 people. The company recorded the type of the most recent visit to a doctor by each employee. A national assessment conducted in 2008 found that 53 percent of all physician visits were to primary care physicians, 19 percent to medical specialists, 17 percent to surgical specialists, and 11 percent to emergency departments. Test at the .01 significance level if Isaac employees differ significantly from the survey distribution. Click here to see answer by stanbon(57984)

 Question 439326: You have 8 dogs and 5 cats,what is the probability of getting 2 dogs and 2 cats. Click here to see answer by stanbon(57984)

 Question 439321: Question: Assume that the weight loss for the first month of a diet program varies between 6 pounds and 12 pounds, and is spread evenly over the range of possibilities, so that there is a uniform distribution. Find the probability of the given range of pounds lost. More than 11 pounds Click here to see answer by stanbon(57984)

 Question 439361: a password consits of four letters followed by THREE-DIGIT NUMBER. HOW MANY PASSWORDS Are possible if there are no restrictions. 58P₂= Click here to see answer by stanbon(57984)

 Question 439378: Q: if the random variable z is the standard normal score, is it true that P(z <-6) could easily be approximated without referring to a table? Why or why not? I don't even know where to begin, please help. Thank you. Click here to see answer by stanbon(57984)

 Question 439403: What is the probability that a 31-day month will have five Mondays? Assume that there is an equal chance of any one of the seven days being the first day of a month. Click here to see answer by edjones(7569)

 Question 439417: Assuming the following: Null Hypothesis: μ = 5 3 ≤ x ≤ 7 a. Assuming σ = 1 and n = 25, what percent of the time will you: 1. accept the null hypothesis when it is true? 2. reject the null hypothesis when it is true? 3. demonstrate 1 & 2 on a normal curve. Click here to see answer by robertb(4012)

 Question 439441: A multiple-choice test has five questions, each with five choices for the answer. Only one of the choices is correct. You randomly guess the answer to each question. What is the probability that you answer the first two questions correctly? Click here to see answer by stanbon(57984)

 Question 439480: In how many ways can 10 runners finish a race first, second, or third? I don't understand how to even set this up to solve it! Click here to see answer by vleith(2825)

 Question 439495: In a study of drivers under the age of 25, 30 wear seat bells and 21 do not. If one driver is chosen at random, what is the probability that he or she does not wear a seat belt? Click here to see answer by stanbon(57984)

 Question 439651: A particular classroom has 24 seats and 24 students. Assuming the seats are not moved, how many different seating arrangements are possible? Write your answer in scientific notation. Click here to see answer by shantalboodram(15)

 Question 439670: Mr. Santos has a new game. It consist of 65 cards numbered from 1 to 65. In order to win, he must draw 3 cards in a row that have 5 on them. There are 16 cards that have at least one digit equal to 5. After drawing a card, it is set aside. If Mr. Santos draws seven cards, and none of them has a 5, what is the probability that he will win the game on the next three draws? Click here to see answer by stanbon(57984)

 Question 439610: Find the probability of correctly answering the first 2 questions on a multiple choice test if random guesses are made and each question has 5 possible answers. Click here to see answer by jorel1380(2518)

 Question 439673: 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 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 at α = .05? (a) State the hypotheses 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(57984)

 Question 439688: Can any one help me with this problem. Suppose that I am rolling 2 dice. If the total comes out to an odd number I am paid \$1. If the total is 4 or 8 then I am paid \$5. What is the expected value of this game? Thanks, Kim Click here to see answer by solver91311(17077)

 Question 439712: Assume that the average annual salary for a worker in the United States is \$30,000 and that the annual salaries for American are normally distributed with a standard deviation equal to \$7,000. Find the following: a)What percentage of Americans earn below \$22,000? b)What percentage of Americans earn above \$42,000? Click here to see answer by stanbon(57984)

 Question 439750: What is the probability that a 31 day month will have 5 Mondays. Assume that there is an equal chance of any one of the seven days being the first day of the month. Show all working. Click here to see answer by edjones(7569)

 Question 439682: During the first half of the NBA season, the LA lakers won half of their games. What percentage of the remaining half must win to increase the winning by 55% Click here to see answer by edjones(7569)

 Question 439766: A certain type of machine requires repairs once every two years on average. What is the probability that such a machine will work at least two years without requiring repair? A company has four such machines which operate independently. What is the probability that at least one of them will not need repair in the next 2 years? Click here to see answer by edjones(7569)

 Question 439780: Evaluate: a. 5! = b. small (7) P small (5) 7P5 = c. small (7) C cmall (5) 7C5 = Click here to see answer by stanbon(57984)

 Question 439779: 1. How many combination are there of 9 identical cars if I am picking 3 of them to test drive? 2. A garden has a total of 10 flowers. Three are yellow, two are white, and five are blue. If you select 2 at random without replacement, find the probability that a. non of the flowers are yellow b. at least one of the flowers are yellow Click here to see answer by stanbon(57984)

 Question 439775: 1. One card is selected at random from a deck of cards. Find the probablity that the card is a red OR a 10 2. A license plate is to contain 3 letters followed by 3 digits. If the first letter can't be X or Z, ad repetition is permitted, fnd the number of license plates possible. Can you please show the work so I can understand how to work this problem Thank you Click here to see answer by stanbon(57984)

 Question 439869: A jar contains 18 nickels, 25 dimes, and 12 quarters. What is the probability picking three dimes, replacing each after it is drawn. Show all work Click here to see answer by richard1234(5390)

 Question 439882: what is the probability that three cards chosen from a deck of 52 playing card will all have even numbers(from 2 to 10)? Click here to see answer by stanbon(57984)

 Question 439956: please help me with this problem! A tugboat moves at a rate of 10 mph in still water. it travels 24 miles upstream and 24 miles downstream in a total time of 5 hours. what is the speed of the current? Please and thank you. Click here to see answer by jorel1380(2518)

 Question 439971: given a mean test score of 78 with a standard deviation of 5. calculate a z-score for a test score of 85 Click here to see answer by robertb(4012)

 Question 439786: 1. If the mean is 40 an the standard deviation is 8, what percent of data is between 32-48? 2. If the mean is 40 and the standard deviation is 6, what number is two standard deviation below the mean? Click here to see answer by robertb(4012)

 Question 440036: i need help... suppose you choose at random a real number X from the interval [2, 10]. Find the PDF f_X(x) and the probability of an event E for this experiment, where E is a subintercal [a,b] of [2,10]. thanks for your help Click here to see answer by robertb(4012)

 Question 439158: Given the binomial distribution with n = 14 and p = 0.37, would the normal distribution provide a reasonable approximation? Why or why not? Click here to see answer by robertb(4012)

 Question 440040: A point is chosen at random from the interior of a right triangle with height 1 and base 1. Let Y denote the distance from the chosen point to the base of the triangle. Find the PDF and CDF of Y. Click here to see answer by robertb(4012)

 Question 440095: A coin is flipped and then a number from 1 to 4 is selected at random from a bag. a. construct a tree diagram showing all the possible outcomes b. How many points are there in the sample space c. Find the probability that a tail is flipped and a 3 is selected d. Find the probablity that a head is flipped or a number less than 3 is selected. e. Find the probabliy that a head is flipped and an even number is selected Click here to see answer by stanbon(57984)

 Question 440091: Each of the eight digits 1,2,3,4,5,6,7,8 is written on a piece of paper and all of the 8 pieces of paper are then placed in a hat. Find the probability that the number selected is a. odd b. greater than 6 c. odd AND greater than 5 d. odd OR greater than 5 If the same eight pieces of paper are placed in a hat, find the probability WITHOUT replacement that 2 pieces selected from the hat will a. both be odd b. both be less than 4 Click here to see answer by stanbon(57984)

 Question 440088: what is the probability of choosing exactly one woman among 2 women and 4 men forming 3 commute. Click here to see answer by stanbon(57984)

 Question 440087: Out of 153 people who visited Publix last night, 45 of them purchased a sub sandwhich. Find the empirical pobability that the next person to enter Publix will purchase a sub sandwhich. Click here to see answer by stanbon(57984)

 Question 440007: If a fair coin is tossed 200 times what is the probability that you will see between 80 and 120 heads? If the Normal approximation to the Binomial distribution applies, use it. If not use the Binomial distribution methods. Click here to see answer by stanbon(57984)

 Question 440006: On a History test, where the student grades are distributed normally, the average grade was 78 and the standard deviation was 10. Determine the numeric score of two students whose standard scores (a.k.a. z-scores) were -0.6 and 1.2, respectively. Click here to see answer by stanbon(57984)

 Question 440129: Giving a test to a group of students, the grades and gender are summarized below A B C Total Male 7 8 3 18 Female 10 14 11 35 Total 17 22 14 53 If one student is chosen at random, Find the probability that the student was NOT a male that got a "B" Enter your answer as a fraction. Click here to see answer by ewatrrr(10682)

 Question 440136: I randomly take three lightbulbs from a box containing 80 lightbulbs of which 5 are defective. What is the probability that none of the three lightbulbs I take are defective? What is the probability that at least one of the lightbulbs I take is defective? Click here to see answer by ewatrrr(10682)

 Question 440004: The scores on a National High School English Test are normally distributed with an average sore of 83 and a standard deviation of 6. What is the probability that someone will score between 80.24 and 96.26? Click here to see answer by ewatrrr(10682)

 Question 440002: If the completion time for a task is normally distributed with a mean of 15 seconds and a standard deviation of 2.5 seconds, what is the probability of getting a time less than 9.7 seconds? Click here to see answer by ewatrrr(10682)

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