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What is the probability that at least 2 people have the same birth month in a group of 8 people?
Wiki User
∙ 9y ago
Birth months are not uniformly distributed across the year. However, if yo assume that they are, the probability is 0.9536 (approx).
Wiki User
∙ 9y ago
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What is the probability of at least one birthday match among a group of 41 people?
The probability of at least 1 match is equivalent to 1 minus the probability of there being no matches. The first person's birthday can fall on any day without a match, so the probability of no matches in a group of 1 is 365/365 = 1. The second person's birthday must also fall on a free day, the probability of which is 364/365 The probability of the third person also falling on a free day is 363/365, which we must multiply by the probability of the second person's birthday being free as this must also happen. So for a group of 3 the probability of no clashes is (363*364)/(365*365). Continuing this way, the probability of no matches in a group of 41 is (365*364*363*...326*325)/36541 This can also be written 365!/(324!*36541) Which comes to 0.09685... Therefore the probability of at least one match is 1 - 0.09685 = 0.9032 So the probability of at least one match is roughly 90%
What is the probability that at least 2 people in a random group of 6 people have a birthday on the same day of the week?
1-365/[(365-6)*365^6] = 1 Is this O.K ?
Find the probability that in a family of 4 children will be a at least 1 boy b At least 1 boy and 1 girl Assume that the probability of a male birth is 12?
http://answerboard.cramster.com/statistics-and-probability-topic-5-292446-0.aspx
If the overall percentage of success in exam is 60 .what is probability that ouit of group of 4 students.at least one has passed?
This is a Binomial Probability Distribution; n=4, p=0.6. The probability of at least 1 passed is equal to the probability of 1-none passed; so x=0. The probability of x=0 (with n=4, p=0.6) is 0.0256. So, the probability of at least 1 passed is 1-0.0256 or 0.9744.
Each of 3 people chose a number from 1-10 what is the probability that at least 2 people have the same number?
The probability that 2 people have the same number is 2 out of 10
What is the probabililty of at least 2 people same birthday from a group of 12 people?
The probability of at least 2 people in a group of npeople sharing a common birthday can be expressed more easily (mathematically) as 1 minus the probability that nobody in the group shares a birthday. Consider two people. The probability that they don't have a common birthday is 365/365 x 364/365. So the probability that they do share a birthday is 1-(365/365 x 364/365) = 1-365x364/3652 Now consider 3 people. The probability that at least 2 share a common birthday is 1-365x364x363/3653 And so on so that the probability that at least 2 people in a group of n people having the same birthday = 1-(365x363x363x...x365-n+1)/365n = 1-365!/[ (365-n)! x 365n ]In the case of 12 people this equates to 0.16702 (or 16.7%).
Out of 27 students selected for an interview what is the probability that at-least 3 of them have their date of birth in the same month?
The probability is 1.
What is the probability of at least one birthday match among a group of 41 people?
The probability of at least 1 match is equivalent to 1 minus the probability of there being no matches. The first person's birthday can fall on any day without a match, so the probability of no matches in a group of 1 is 365/365 = 1. The second person's birthday must also fall on a free day, the probability of which is 364/365 The probability of the third person also falling on a free day is 363/365, which we must multiply by the probability of the second person's birthday being free as this must also happen. So for a group of 3 the probability of no clashes is (363*364)/(365*365). Continuing this way, the probability of no matches in a group of 41 is (365*364*363*...326*325)/36541 This can also be written 365!/(324!*36541) Which comes to 0.09685... Therefore the probability of at least one match is 1 - 0.09685 = 0.9032 So the probability of at least one match is roughly 90%
What is the probability that at least 2 people in a random group of 6 people have a birthday on the same day of the week?
1-365/[(365-6)*365^6] = 1 Is this O.K ?
Find the probability that in a family of 4 children will be a at least 1 boy b At least 1 boy and 1 girl Assume that the probability of a male birth is 12?
http://answerboard.cramster.com/statistics-and-probability-topic-5-292446-0.aspx
What is the probability that a group of 6 people selected at random from 7 men and 7 women will have at least 3 women?
Using the hypergeometric distribution, the answer is 2114/3003 = 0.7040
If 20 percent of people who enter store buy something and 3 people enter what is the probability of at least one sale?
The probability of at least one event occurring out of several events is equal to one minus the probability of none of the events occurring. This is a binomial probability problem. Go to any binomial probability table with p=0.2, n=3 and the probability of 0 is 0.512. Therefore, 1-0.512 is 0.488 which is the probability of at least 1 sale.
What is the probabililty of at least 2 people same birthday from a group of 13 people?
19.4%CALCULATION:The probability of at least 2 people having the same birthday in a group of 13people is equal to one minus the probability of non of the 13 people having thesame birthday.Now, lets estimate the probability of non of the 13 people having the same birthday.(We will not consider 'leap year' for simplicity, plus it's effect on result is minimum)1. We select the 1st person. Good!.2. We select the 2nd person. The probability that he doesn't share the samebirthday with the 1st person is: 364/365.3. We select the 3rd person. The probability that he doesn't share the samebirthday with 1st and 2nd persons given that the 1st and 2nd don't share the samebirthday is: 363/365.4. And so forth until we select the 13th person. The probability that he doesn'tshare birthday with the previous 12 persons given that they also don't sharebirthdays among them is: 353/365.5. Then the probability that non of the 13 people share birthdays is:P(non of 13 share bd) = (364/365)(363/365)(362/365)∙∙∙(354/365)(353/365)P(non of 13 share bd) ≈ 0.805589724...Finally, the probability that at least 2 people share a birthday in a group of 13people is ≈ 1 - 0.80558... ≈ 0.194 ≈ 19.4%The above expression can be generalized to give the probability of at least x =2people sharing a birthday in a group of n people as:P(x≥2,n) = 1 - (1/365)n [365!/(365-n)!]
If the overall percentage of success in exam is 60 .what is probability that ouit of group of 4 students.at least one has passed?
This is a Binomial Probability Distribution; n=4, p=0.6. The probability of at least 1 passed is equal to the probability of 1-none passed; so x=0. The probability of x=0 (with n=4, p=0.6) is 0.0256. So, the probability of at least 1 passed is 1-0.0256 or 0.9744.
How many people do you need to gather if you want at least to of them to have birthdays in the same month?
13, if you want to be sure. It's impossible for a group of 13 people not to have at least one pair that share a birth month, because there are only 12 months.If you'll settle for a lower probability, thechance that a group of 5 randomly chosen people will contain at least one pair born in the same month is about 3/5, and if you gather 6 people the chance that at least two of them will share a birth month is about 4/5. Those aren't exact probabilities both because the math doesn't work out that way and and because birthdays are not randomly distributed by month ... significantly fewer people are born in February than in August. An exact probability would need to take that into account, and it's frankly more research and math than I want to do unless I'm getting paid for it.
Each of 3 people chose a number from 1-10 what is the probability that at least 2 people have the same number?
The probability that 2 people have the same number is 2 out of 10
What is the probabililty of at least 2 people same birthday from a group of n people then how large ned n for the probability to be greater than 0.5?
It is 1 - 365Cn/365n. This is greater than 0.5 for n greater than or equal to 23.
