STATS

a woman standing on a bridge overlooking a major insterstate wants to know how likely it is that the next 20 out of 50 cars that pass under the bridge are red cars, if she has observed in the past that the probability than any given car on that interstate highway is red is approximately 0.28.

What is the probability?

1. 👍 0
2. 👎 0
3. 👁 74
1. Your question is worded in a confusing way. It sounds like the next 20 cars IN A ROW would have to be red. That would be a very low probability, (0.28)^20 = 8.8*10^-12, and the 30 cars seen after that would not matter.

Don't you mean that you want the probability that exactly 20 of the next 50 will be red?
That probability is
P(20) = (0.28)^20*(0.72)^30^50!/[30!*20!]
= 0.0217

The most likely number of red cars out of 50 would be 14. That probability is
P(14) = (0.28)^14*(0.72)^36* 50!/[14!*36!] = 0.1248
=

1. 👍 0
2. 👎 0
posted by drwls

Similar Questions

1. English

Posted by rfvv on Friday, June 10, 2016 at 11:32pm. 1. The building of the new bridge will go ahead as planned. 2. The building of the new bridge will go ahead as it is planned. (Does #1 mean #2? Is 'it is' deleted?) 3. Lee was

asked by rfvv on June 13, 2016
2. Writing

How can I end this? ____ The bridge I made a model of is the Sydney Harbor Bridge. The bridge is located at Sydney, Australia. The Sydney Harbor Bridge is the main way to cross the Sydney Harbor carrying rail, vehicular, and

asked by Bob on January 13, 2008
3. physics

A bridge is ten meters above a canal and A motor boat going 3minutes per second passes under the center of the bridge at the same time instant that a woman walking 2minutes per second reaches that point and How rapidly are they

asked by Anonymous on August 29, 2011
4. Physics 1

Two skaters, a man and a woman, are standing on ice. Neglect any friction between the skate blades and the ice. The mass of the man is 85 kg, and the mass of the woman is 53 kg. The woman pushes on the man with a force of 58 N due

asked by Anonymous on February 11, 2014
5. Physics!

Two skaters, a man and a woman, are standing on ice. Neglect any friction between the skate blades and the ice. The mass of the man is 81 kg, and the mass of the woman is 60 kg. The woman pushes on the man with a force of 50 N due

asked by Tiffany on February 2, 2011
6. PHYSICS

Two skaters, a man and a woman, are standing on ice. Neglect any friction between the skate blades and the ice. The mass of the man is 88 kg, and the mass of the woman is 58 kg. The woman pushes on the man with a force of 56 N due

asked by Anonymous on October 4, 2015
7. physical

Two skaters, a man and a woman, are standing on ice. Neglect any friction between the skate blades and the ice. The mass of the man is 84 kg, and the mass of the woman is 68 kg. The woman pushes on the man with a force of 50 N due

asked by Tara on February 13, 2013
8. physics

Two skaters, a man and a woman, are standing on ice. Neglect any friction between the skate blades and the ice. The mass of the man is 84 kg, and the mass of the woman is 49 kg. The woman pushes on the man with a force

asked by Thomas on January 5, 2017
9. Physics

Two skaters, a man and a woman, are standing on ice. Neglect any friction between the skate blades and the ice. The mass of the man is 81 kg, and the mass of the woman is 60 kg. The woman pushes on the man with a force of 50 N due

asked by Tiffany on February 3, 2011
10. PHYSICS

Two skaters, a man and a woman, are standing on ice. Neglect any friction between the skate blades and the ice. The mass of the man is 95 kg, and the mass of the woman is 55 kg. The woman pushes on the man with a force of 57 N due

asked by TVIX on October 21, 2011

More Similar Questions