View Full Version : Probability?
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}