Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

xEnOnn Group Title

There are 25 students at a bus stop. It is known that on average, 3 buses arrive at the bus stop in every 20 minutes. What is the probability that the waiting time for the next bus is at least 30 minutes? State the assumptions you need to compute the above probabilities.

  • 2 years ago
  • 2 years ago

  • This Question is Closed
  1. xEnOnn Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    I believe it has got to do with Poisson distribution but I am not sure how to start from it. :(

    • 2 years ago
  2. xEnOnn Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    So the number of buses has become the interval instead? But isn't time the only unit for the interval in poisson?

    • 2 years ago
  3. xEnOnn Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Also, the question asked for the assumptions that were made in computing the probabilities. What assumptions have we made in this calculation? I don't understand what kind of assumptions have we made.

    • 2 years ago
  4. Tributized Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    nice prof pic lol..

    • 2 years ago
  5. xEnOnn Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Also, to have X~Pois(20/3), and find P(X>=30)=1-P(X<30), The P(X<30) is very close to 1. This would make P(X>=30)=1-1=0, which looks weird.

    • 2 years ago
  6. Zarkon Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    wouldn't it be Poisson\(\displaystyle\left(\frac{3}{20}\cdot 30\right)\)=Poisson(4.5)

    • 2 years ago
  7. Zarkon Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Calculate P(X=0)

    • 2 years ago
  8. xEnOnn Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Why calculate the probability of X=0?

    • 2 years ago
  9. Zarkon Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    0 buses arriving in the first 30 mins

    • 2 years ago
  10. xEnOnn Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    OHH!!! wow!! This is smart!

    • 2 years ago
  11. Zarkon Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    time to teach..be back later

    • 2 years ago
  12. xEnOnn Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    wow! this feels counter intuitive but somewhat logical. i wouldn't have thought of it. It's like so there is zero buses during the first 30mins and so this probability is as good as there is at least a bus after this first 30mins. thanks!!

    • 2 years ago
  13. xEnOnn Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    ok sure! Thanks for you help!!!

    • 2 years ago
    • Attachments:

See more questions >>>

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.