probability

  1. R

    Bayesian exercise

    -2 down vote favorite I cant get my head round the following exercise: You are testing dice for a casino to make sure that sixes do not come up more frequently than expected. Because you do not want to manually roll dice all day, you design a machine to roll a die repeatedly and record the...
  2. W

    Normal Distribution

    Assuming that the number of marks scored by a candidate is normally distributed, find the mean and the standard deviation, if the number of first class students(60% or more marks) is 25, the number of failed students(less than 30%marks) is 90 and the total number of candidates appearing for the...
  3. B

    NCA Office Pool Win Probability

    Hello, I run a small NCAA office pool website where folks make predictions about the outcome of each game in a 64-team tournament that consists of six, single elimination rounds. Each correct prediction is worth a standard amount of points, and you compete in leagues against friends and...
  4. J

    Number of Possible Orders

    In a regional spelling bee, the 8 finalists consist of 3 boys and 5 girls. Find the number of sample points in the sample space S for the number of possible orders at the conclusion of the contest for: a) all 8 finalist. b) the first 3 positions. My solutions: a) 8! = 40,320 sample points...
  5. B

    Probability Q help, uses combinatorics, Poisson-Distr and possibly Multinomal

    Place successively and independent of each other 20 particles into 10 boxes. Hereby, each of the 10 boxes is chosen with the same probability. a) Determine the probability of the following events 1. Exactly one particle is in box 1. 2. At least one particle is in box 1. b) Give the...
  6. N

    Real life probability problem

    So I'm wondering if someone can solve this problem for me. Some work was done in our kitchen yesterday and the fridge had to be moved. I noticed some pretty bad scratches on the wood floor that were clearly from the fridge. The fridge hadn't been moved for 39 days prior. So what is the...
  7. M

    S1 Statistics question help! Majorly stuck

    Hi I have 3 statistics questions that I would like help with, 1. When Albert eats in a certain restaurant, he always eats either chicken or beef for his main course. And he always eats either sponge pudding or ice cream for his dessert. The probability that he eats chicken is 1/3, the...
  8. N

    What distribution is better in these situations?

    I'm new in statistics and probability and I'm a little lost about what distribution is better in these situations: If a tumor is malignant or not --> Bernouilli Number of entries in an emergency service during a night, know that on average 20 entries are observed per night. --> Poisson Tumor...
  9. G

    Probability of observing mean difference/compute ranksum

    Hi everyone, would appreciate some help on these three questions. If possible with calculations so that I can understand more easily! Suppose the endowment effect experiment were run with 5 people, 3 sellers and 2 buyers. Subjects arrive in the lab and pick numbers 1-5 out of the hat. If they...
  10. J

    Where did I go wrong in these three questions?

    Hi everyone, I just finished taking an online test and found out that some of my answers were wrong. The questions and answers can be found in attached screenshots. Question 1 (Suppose T and Z are random variables) https://s9.postimg.org/7krqdwirz/image.png I got no credit looks like it is...
  11. E

    Definition of random variable with respect to event space

    It is given that: We toss two dice with sample space Ω = {(i, j), 1 ≤ i, j ≤ 6} and the σ-algebra is generated by the events Ak = {(i,j) : max(i,j) = k} (k = 1, . . . , 6). Show that whereas X1(i, j) = max(i, j) is a random variable in the corresponding probability space, X2(i, j) = i + j is...
  12. S

    Conditional Monthly Risk Calibration for a trading model

    Hi, I have a trading system with a portfolio of assets (long and shorts) with daily market returns. I want to overlay a risk management to my trading system that calibrate my portfolio positions on a daily basis so that a monthly portfolio loss of lets say 20% only occurs 1% of the time...
  13. E

    Row problem with mandatory empty seats

    Here is the exact question: Suppose that 39 students (you being one of them) are randomly seated in a long row of 120 seats. How likely is it that you will not have a direct neighbor? What I've understood: that one the side you can only have one seat with no neighbor next to you and one...
  14. D

    Racing

    Hi all, I need some help with some statistical work: So, I am trying to understand how I can transform time into probability. I have 2 teams playing a game for 10 minutes. One team scores 1 pt per each minute and the other team takes 1,5 minutes in average to score one point. I want...
  15. R

    Bionomial Probability Distributions

    51% of men consider themselves professional baseball fans. You randomly select 10 men and ask each if he considers himself a professional baseball fan. Find the probability that the number who consider themselves baseball fans is (a) exactly five, (b) at least six, and (c) less than four (a)...
  16. L

    Probability Questions - Cannot seem to figure out

    I have been working on this problem for a few days now and cannot seem to at least find a formula or example in my book that works. Any help would be very much appreciated, thanks! In 2009, according to a Harris Interactive poll, 52% of American college graduates have Facebook accounts...
  17. S

    Game Probability Question

    Hi, I am playing a game. I win with an 88% chance and lose with 12% probability. If I have won 20 games in a row what is the probabilty that I will lose the next game. If you can figure out the answer and provide also the calculation logic that would be great. Thanks B
  18. E

    Gage R&R results to usable data

    This is for my thesis & i'm stumped. Please help. A Gage R&R was done comparing two inspection tools to each other. These tools measure the section modulus of wood, which is used to calculate the SI and whether or not we replace the wood. The measurements using the tools were normalize, that...
  19. R

    Calculation of expected values for chi-squared test

    Folks I need to work out the probability that a set of survey results occurred by chance, and I intend to use a chi-squared test. However, I haven't studied mathematics formally since I was 16, and I need someone to confirm whether my calculations of expected values are accurate and, if not...
  20. M

    Probability of more than 5 responses surveying two locations with different response

    You are looking for people between 16 to 23 years to answer a survey. Assume houses on First Street, based on copious amounts of empty beer bottles in front yards and your past experience, has a chance of yielding 16 to 23 year olds to answer your survey of 20% per house. Houses on Second...