Question

In the most recent election, 19 percent of all eligible college students voted. If a random sample of 20 students were surveyed, find the probability that exactly half voted in the election.

Answer 1

Answer:. This would be 0.81^20 for none of the 19=0.0148

Step-by-step explanation:With a tree diagram, there are two possibilities, one is ND from 1 D from 2, with probability (5/8)(2/5)=(1/4) and the other is (3/8)(3/5)=9/40 That would be 19/40 for the answer.

3. Poisson parameter lambda=5

for P(0), it is e^(-5)(5^0)/0! or e^(-5)=0.0067

 

for P(1), it is e^(-5)(5^1)/1! or 5e(-5)

The total probability is 6e^-5 or 0.0404

4. the mean is 1000 hours, so lambda is the reciprocal or 1/1000

the probability it will last <800 hours is 1-e^(-800*1/1000) or 1-e^(-.8)=0.5507

5. assume p=0.4 since it ca't be 4

sd is sqrt (np*(1-p))=sqrt (6*0.6=sqrt(3.6)=1.90