9th grade probability problems?
Can you please explain how to do these?
1. The probability that the weather will be acceptable for a launch of a satellite over the next 3 days is 70% each day. What is the probability that the weather will be acceptable at least 1 of the next 3 days?
2. A poll shows that 60% of a school district's home owners factor an increase in property tax to fund a new high school. What if the probability that exactly 4 of 5 people chosen at random favor a tax increase?
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1. To find the probability for AT LEAST 1, it is usually easiest to find the probability of NONE, then subtract this probability from 1.
So if the probability of acceptable weather on each day is .70, then the probability of inacceptable weather on any one day is .30. So, three days in a row means .30*.30*.30 = .027 probability of no acceptable days, so 1-.027 = .973 is the probability of at least ine acceptable day.
2. This is a binomial problem with n = 5, p = .6, and r = 4. The probability that x = r is
nPr * p^r * (1-p)^(n-r) = 5 * .6^4 * .4
You can check your answer at
http://stattrek.com/online-calculator/binomial.asp...
right here we've, u . s . Cd's = 4, rock/roll Cd = a million, tejano Cd's = 3, rap Cd's = 2 finished Cd's = 4 +a million +3 +2 = 10 Probabilty for tejano = 3/10 ........... answer threat for rap Cd's = 2/9 ......... answer