Question 1179350: If it estimated that 30% of all students who fall under the Business Economics and Management Department at Richfield have a valid driver's license. What is the probability of this in a sample of 10 students?
(I) Exactly 4 have a valid driver's license?
(II) At least 2 have a valid driver's license?
(II) More than 9 have a valid driver's licence?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! exactly 4 is 10C4(0.3)^4*(0.7)^6=0.2001
or 2nd VARS binompdf(10,.3,4)
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at least 2, look at prob of 0 and 1, add them and subtract from 1
p(0)=0.7^10=0.0282
p(1)=10*0.3*0.7^9=0.1211
they add to 0.1493, so the answer is 1-0.1493=0.8507
or 1-binompdf(10,0.3,1), which performs the same calculation.-
more than 9 is all 10, and that is 0.3^10=0.0000059
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