Question 1078704: Will try again I asked this question on 4/24 none ever seems to answer questions here...
A college has 25,000 students, of whom 10000 are older than 25. The registrar draws a simple random sample of 400 students.
The expected value for the number of students in the sample who are older than 25 is _______________.
The standard error for the number of students in the sample who are older than 25 is ____________________________.
The expected value for the percentage of students in the sample who are older than 25 is _____________.
The standard error for the percentage of students in the sample who are older than 25 is ________________.
The percentage of students in the sample who are older than 25 will be around ____________, give or take ________________or so.
Found 2 solutions by Boreal, Alan3354:
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! probability is 0.4 that older than 25.
E(x)=400*0.4=160
using the SE below, and multiplying by 400, it is 9.8
E(x) for percentage is 40%
SE is sqrt (.4*.6/400)=0.02445 or 2.45%
Using a 95% interval, (0.352, 0.448), or for the answer, 40%, give or take 4.8%
mean is 160
sd is sqrt (variance)=sqrt (400*.4*.6)=96; sqrt (96)=9.8, which is what was shown above.
Answer by Alan3354(69443)  (Show Source):
You can put this solution on YOUR website! No one answers a question here?
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