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tytee12
Mar 28, 2007, 07:36 PM
If 40% of the community goes to the car wash, find thes probabilitites for a sample of 13 people:

Exactly 7 people go to the car wash.

At most 8 people go to the car wash

At least 6 people go to the car wash.

Less than 5 people go to the car wash.

worthbeads
Mar 28, 2007, 07:59 PM
Can you rephrase the question please.

Capuchin
Mar 28, 2007, 11:46 PM
Yes, your question makes no sense, you're saying that exactly 0.40 percent go to the carwash, so out of 13 people, 5.2 will go to the car wash.

So exactly 7 has a probability of 0
8 or less has a probability of 1
6 or more has a probability of 0
less than 5 has a probability of 0.

Do you see how the question doesn't make sense?

galactus
Mar 29, 2007, 04:35 AM
This is classic binomial probability:

a. C(13,7)(0.40)^{7}(0.60)^{6}

b. \sum_{k=0}^{8}C(13,k)(0.40)^{k}(0.60)^{13-k}

c. \sum_{k=6}^{13}C(13,k)(0.40)^{k}(0.60)^{13-k}

d. \sum_{0}^{4}C(13,k)(0.40)^{k}(0.60)^{13-k}