/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q.4.56 How many people are needed so th... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

How many people are needed so that the probability that at least one of them has the same birthday as you is greater than 12?

Short Answer

Expert verified

The probability the same birthday found to be253.

Step by step solution

01

Given Information

The probability that at least one person has the same birthday as me is greater than12.

02

Calculation

Suppose that there are npeople.

The probability that non of them has the same birthday as me is simply

364365n

03

Substitution

So the probability that at least one person has the same birthday as me is greater than 12if and only if

1-364365n≥12

⇔364365n≤12

⇔nlog364365≤log12

⇔n≥252.65.

04

Final answer

The probability that at least one person has the same birthday as me is greater than12has found to be253.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

If X has distribution function F, what is the distribution function of the random variable αX + β, where α and β are constants, α≠0?

An urn has n white and m black balls. Balls are randomly withdrawn, without replacement, until a total of k,k…nwhite balls have been withdrawn. The random variable Xequal to the total number of balls that are withdrawn is said to be a negative hypergeometric random variable.

(a) Explain how such a random variable differs from a negative binomial random variable.

(b) Find P{X=r}.

Hint for (b): In order for X=r to happen, what must be the results of the firstr−1 withdrawals?

From a set of n elements, a nonempty subset is chosen at random in the sense that all of the nonempty subsets are equally likely to be selected. Let X denote the number of elements in the chosen subset. Using the identities given in Theoretical Exercise 12of Chapter1, show that

E[X]=n2−12n−1

Var(X)=n⋅22n−2−n(n+1)2n−22n−12

Show also that for n large,

Var(X)~n4

in the sense that the ratio Var(X) ton/4approaches 1as n approaches q. Compare this formula with the limiting form of Var(Y) when P{Y =i}=1/n,i=1,...,n.

There are two possible causes for a breakdown of a machine. To check the first possibility would cost C1 dollars, and, if that were the cause of the breakdown, the trouble could be repaired at a cost of R1 dollars. Similarly, there are costs C2 and R2 associated with the second possibility. Let p and 1 − p denote, respectively, the probabilities that the breakdown is caused by the first and second possibilities. Under what conditions on p, Ci, Ri, i = 1, 2, should we check the first possible cause of breakdown and then the second, as opposed to reversing the checking order, so as to minimize the expected cost involved in returning the machine to working order?

Let X represent the difference between the number of heads and the number of tails obtained when a coin is tossed n times. What are the possible values of X?

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.