probability

  1. M

    Defintion of a random variable

    I have read two defintions for a random variable. 1. It is a function from the set of all posisible outcomes to the real line. For example Y("male")=0 2. A variable where known probabilities are associated with sample outcomes. Which one is correct? Defintion 1 does not include a probability...
  2. M

    Support vs sample space

    I understand that the term support is not used in the same sense in mathamtics and statistics. However, I cannot really understand difference between support and sample space when it comes to statistics. Could you say that the support isa subset of the sample space, i.e. all sample points that...
  3. Y

    Probability question

    The govt. of ontario decided it would try to raise money by installing photo radar cameras on the 401 highway acros the top of Toronto. The camera would be set to record the speed of those travelling more that 135 km/h and send them a ticket for $200. It would only run the program between the...
  4. Y

    Am I using the binom.dist properly?

    Q -Stats classhas 60 students in it. The class lasts for three hours and the students ask questions at a rate of about 3 questions per hour. Model this situation with an appropriate binomial distribution and determine the probability of receiving more than 5 questions in a class. My answer...
  5. W

    Odds Ratio to Probability of Success

    We ran a logistic regression model with Passing the certification exam (0 or 1) as an outcome. We found that one of the strongest predictors is the student's program GPA, the highest the program GPA, the highest the odds of passing the certification exam. Standardized GPA: p-value < .0001, B...
  6. C

    Combined Probability

    How do I solve this problem? Four departments: PE (6 team members), QA (8 team members), EE (5 team members), and AS (28 team members). If 8 team members are randomly selected, what is the probability that you will: 1) Have at least one team member from each department 2) All AS team members...
  7. V

    Probability Question

    If you toss 100 fair coins (chance is 50% that it is heads) What is the chance that you will get 60 or more heads. Does anyone know how to calculate this probability? Thank you in advance!
  8. M

    Nonparametric data analysis

    I'm asking for advice. Topic of my research is brain iron accumulation. My task is the next . I have one dependent variable that is cathegorical and binominal(patient has the pathology or does not). And six independent variables that are continuous and nonpatametric. The question is :how can i...
  9. C

    Empirical Survivor Function (esf)

    From page 26, chapter 2 of the reference "Tableman, M., & Kim, J. S. (2003). Survival analysis using S: analysis of time-to-event data. CRC press", I have found the definition of the empirical survivor function (esf) is S(t) = (number of individuals > t)/n . But from page 80, chapter 3 of...
  10. K

    Tires Probability Question

    Question: You recently bought a new set of four tires from a manufacturer who just announced a recall because 2% of that particular brand of tires are defective. What is the probability that at least one of your tires is defective? You may assume that the tires are defective independently of...
  11. B

    Combining two sources of uncertainty

    I will use an imperfect dice for simplicity. Let's assume there are two factors that influence the probability of the results obtained from throwing a dice: 1) the way the dice is thrown and 2) imperfections of the dice. Let's assume that we know what is the probability distribution of the...
  12. E

    Probability HW help

    I need help with these problems. I worked them out, got answers, and checked the back of the book to see if I got them correct. A pair of six-sided balanced dice are rolled. What are the probabilities of getting the sum of the face values as follows? (a) 8 (b) 6 or 9 (c) 3, 8, or 12 (d)...
  13. K

    Help with what a question is asking

    I know how to calculate probabilities, but I want to make sure that I am understanding the question. "What is the probability that the Dow Jones Index will increase by more than 11% in the coming year?" and "What is the probability Dow (X) will decrease more than 11% in the coming...
  14. C

    Simple Set THeory/Probability Problem

    Hello all, I'm very new to statistics as well as this forum, so please bear with me. I've tried solving this for about 30 minutes now and I've made pretty much 0 progress on it. The question is: Suppose that evens A and C are mutually exclusive. P(not A)=0.7, P(CB)=0.4, what are the...
  15. S

    Probability of a subjective event based on historical subjective data . Forecasting

    Lately i developed an idea of understanding the behavior of kids in their childhood. I was wondering how kids are molded into different adults in no time. So i created a problem statement based on my ideology and hoped to solve using applications of mathematics. Coming from a non engineering and...
  16. S

    Probability of H/T Score AND F/T Score Being Specific Scores...

    Hi All, Just trying to answer something in my mind... If I had calculated (using poisson) the chances of various scores occurring in a football match, in theory, I could get a %age chance of a full time scoreline. Likewise, I could perform all the same calculations for the half time score...
  17. G

    Minimum CDF of non-independent random variables

    How can I find the CDF for F_{X,Y}={x,x} if X,Y are not-independent. In other words, what will be Pr{min(X,Y)<x} if X,Y are not-independent? If I already know the individual CDF of both X and Y, i.e. F_{X}(x) and F_{Y}(x), can they be useful to compute the Pr{min(X,Y)<x}, where X,Y are...
  18. L

    sampling/probability/correlation?

    I have in my course this problem do you have any idea from people who work daily with stats ? the question is like that: the following data are available concerning the products of a firm taken at random from four factories, and classified according to level of quality: Factory A : from low to...
  19. L

    Exponential Distribution Conditional Probability

    Hello, I have been working with Exponential Distribution problems, but have not come across a problem like this one with both Exponential Distribution and Conditional Probabilities: If the lifetime of an electronic equipment follows an Exponential Distribution with parameter 0.1 hour. Given...
  20. K

    Measuring the effect of in-store Promotions

    Hello, I am testing the effect of a new in-store promotion technique (treatment). It is applied during product promotions, as a compliment to regular promo displays, to further improve sales. I have the treatment in only one store but on several products promotions in that store (I have...