1. ## please i need help in solving these questions

hi all, please can anyone help me

1. The internal auditing staff of an local manufacturing company performs a sample audit each quarter to estimate the proportion of accounts that are delinquent more than 90 days overdue. The historical records of the company show that over the past 8 years 13 % of accounts are delinquent. For this quarter, the auditing staff randomly selected 25 customer accounts. What is the probability the no more than 40 accounts will be classified as delinquent?

2. A PH.D graduate has applied for a job with two universities, A and B. the graduate feels that she has a 60% chance of receiving an offer from university A, and a 50% chance of receiving an offer from university B. if she receives an offer from university B, she believes that she has an 80% chance of receiving an offer from university A:
- What the probability that both universities will make her an offer?
- What the probability that at least one university will make her an offer?

3. ## Re: please i need help in solving these questions

question no.1 i didn't know to start
for the second question i solve it like this

p(A and B) = p(A) * p(A/B)= .6 * .8 = .48
p(A or B) = p(A) + p(B) - p(A and B) = .6 + .5 - .48 = .62 .... but i got zero

4. ## Re: please i need help in solving these questions

For this quarter, the auditing staff randomly selected 25 customer accounts. What is the probability the no more than 40 accounts will be classified as delinquent?
I would say the probability was zero because if you only surveyed 25 accounts you obviously can't find 40 accounts delinquent since 40 > 25

Are you sure you provided all the information from the question?

5. ## Re: please i need help in solving these questions

Originally Posted by help101
p(A and B) = p(A) * p(A/B)= .6 * .8 = .48
You messed up the equation: P(A and B) = P(A|B)*P(B)

6. ## Re: please i need help in solving these questions

sorry 250 accounts

7. ## Re: please i need help in solving these questions

Originally Posted by noetsi
Are you sure you provided all the information from the question?
I was wondering the same thing.

8. ## Re: please i need help in solving these questions

Originally Posted by Dason
You messed up the equation: P(A and B) = P(A|B)*P(B)
ohhhhhhhhhhh opps

9. ## Re: please i need help in solving these questions

And for question 1 you might want to use the binomial distribution.

10. ## Re: please i need help in solving these questions

Well at least we found a case where p = o (in the original example)

11. ## Re: please i need help in solving these questions

for 2 b
p(A or B) = p(A) + p(B) - p(A and B) = .6 + .5 - .40 = .7 right :\$

12. ## Re: please i need help in solving these questions

Originally Posted by noetsi
Well at least we found a case where p = o (in the original example)
good job

13. ## Re: please i need help in solving these questions

Looks good to me.

14. ## Re: please i need help in solving these questions

Originally Posted by Dason
And for question 1 you might want to use the binomial distribution.
how???? ????

15. ## Re: please i need help in solving these questions

Have you ever learn/heard of the Binomial distribution? If yes you should be able to know what kind of "experimental outcome" you can use it to model.

http://en.wikipedia.org/wiki/Binomial_distribution

Recently I have also tried to explain this once. Maybe you would take a look (#2) and answer the question posted.