Question 1084580: 12. The director of admissions estimates admissions based on past experieces.
Admissions: 1000 | 1500 | 2000 | 2500 | 3600 | 4500
Probability: .07 | .08 | .10 | 0.25 | 0.4 | .1
what is the expected number (mean) of admission?
13. The online access computer service industry is growing at an extraordinary rate. Current estimates suggest that only 43% of home-based computers have access to online services. This number is expected to group quickly over the next five years. Suppose 10 people with home-based computers were randomly and independently sampled. Find the probability that at least 6 of those sampled currently have access to online services.
14. it is claimed that a new medicine for acne is 80% effective - that is, of every 100 persons who apply it, 80 show significant imporovement. It is applied to the affected are of a group of 15 people. Let X be the number who show significant improvement. Find the mean of X.
15. The mean age at which men in the US marry for the first time is 24.8 years. The shape and the standard deviation are unknown. For a random sample of 100 men, what is the likelihood (probability) that the average age at which they were married for the first time is lant that 25.1 years? Assume that the standard deviation os the population is 2.5 years.
16. A may 207 Gallup Poll found that only 10 of the randowm sample of 200 adults approved attepts to clone a human. Find the margiin of error for this poll if you want 95% confidence in our estimate of the percent of American adults who approve of cloning humans.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! The expected value is x*p(x)=70+120+200+500+1440+450=2780
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This is 10C6*0.43^6*0.57^4, the 10C6 being the number of ways 6 specific items can occur out of 10.
=0.1401
for 7, it is 0.0604
for 8, 0.0171
for 9, 0.0029
for 10, 0.0002
At least 6 is 0.2207 probability
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Mean is expected value or 15*0.80=12
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this doesn't say whether greater than 25.1 or less than 25.1
z>(x-mean)/sd/sqrt(100)=(25.1-24.8)*10/2.5 so z>3/2.5 or z>1.2 or 0.1151. Less than would be 0.8849, the complement.
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probability point estimate is 0.05
std error is sqrt (0.05*0.95/200)=0.0154
95% CI uses 1.96*0.0154=0.0302
95% CI is (0.02, 0.08)
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