random variable

  1. J

    normal distribution

    Hi everyone! I have a question about the answer of question 19a and e. question a: Find the probability that X is greater than 60. Why do they do 0,5 -0,3944 and not 1 - ...? Question e was: the probability is 0,05 that X is in the symmetric interval about the mean between which two numbers...
  2. 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...
  3. M

    obtain inter-aarival from bulk arrival

    obtain inter-arrival from bulk arrival I have some data regarding the arrival of customers at a shop. These arrivals are bulk arrivals which have been collected at fixed time intervals (say, t1=0+x,t2=t1+x,t3=t2+x,..). How can I convert these bulk arrivals to inter-arrivals? what about using...
  4. I

    How to evaluate Mean and Variance of Min Function??

    Detail is Given in Image attach
  5. L

    Probability problem - descrete Random variable

    post deleted...
  6. L

    Probability Problem - Random variable

    A company wants to improve waste management in its premises . We put a yellow bin for recovering recyclable materials , a brown to recover compostable materials and another black for waste. Analysis showed that recovered in yellow tray random volume in the interval [ B, B + D] liters. This...
  7. E

    Average distance of the dart (Dartboard)

    Hello I have been struggling with this questions for some time now and I have no idea how to start it. Can you guys give me some tips? "A large circular dartboard is set up with a "bullseye" at the center of the circle, which is at the coordinate (0,0). A dart is thrown at the center but lands...
  8. P

    urgent help need mean variance

    Hi everybody, If a random variable X is distributed in [0,1], can we say E[x]>var[x]? If yes, can you please give me a reference which is stated that or can you please give me the proof? I would be really thankful if you can help
  9. D

    General Linear Mixed Model - how to run!

    Hello, I need some help with how to run a mixed regression with a random factor please! I have a data set with 10 participants, who I conducted observations on multiple times (around 26 observations per participant), so in total I have around 262 observations. For each observation I have 2...
  10. A

    My professor and I disagree on a test's answer. would love to get a second opinion.

    The question is as follows: " In a certain country: 10% of the families have no children 20% of the families have 1 child 30% of the families have 2 children 40% of the families have 3 children one child is randomly chosen from all the children in the country. X is a random variable whose...
  11. A

    Need help with Uniform probability distribution

    Hey guys... I'm sort of confused about these two problems. If you guys can help me out that would be great. Problem: Suppose X is a random variable best describe by a uniform probability distribution with c=3 and d=5 . Find the following probabilities. a) p(x<4) b) p(x>2) Thanks,
  12. T

    Generate random variate: What does this symbol mean?

    Hi. I'm reading a book about how to simulate random variate (from some distribution). But, when i look at the algorithm there, is has a leftarrow symbol, which i'm not sure what does it mean. I try googling but most of the results only state the LaTeX code for such symbol without further...
  13. I

    Random Variable X

    So this question is on my practice final, and the professor provided the work for how to solve it and I cannot figure it out. Suppose that the random variable X has a mean u = 5 and standard deviation o=8. The mean and standard deviation of Y=2X-4 is? The answer is 6 and 16, respectfully...
  14. C

    Probability Mass Functions

    I am having some trouble on understanding some problems on my practice exam. The prompt is: Let X1 and X2 have (the same) probability mass function f(x) := (exp[-n]) * n/x! for x=(0,1,2,3....) where n is a positive constant. Assume that {X1 = a} and {X2 = b} are independent events for any...
  15. A

    Functions of Random Variable.

    Let X be exponential(lambda), and let Y=max(1,X). Find the cdf of Y. Also sketch the cdf. Suppose that X is discrete with pmf p(0)=p(1)=2p(2) (and zero otherwise). Find the pmf and cdf of X. How would you simulate the random variable X starting with U, a uniform[0,1] random variable? That is...