Question 1020370: A recent Wall Street Journal article indicated that 38% of American teenagers use Pandora's online radio service. Suppose a sample of 25 American teenagers are selected. Use this excel output for this binomial problem(https://gyazo.com/0e2c361c443a8e1aa0da1c0dccc2264e)
1.Find the probability that the number of American teenagers who use Pandora's online radio service differs by greater than 2 from the mean.(round answer to 4 decimal places)
2.Find the probability that more than 35% but at most 70% of these American teenagers use Pandora's online radio service.(round 4 decimal places)
Answer by mathmate(429)   (Show Source):
You can put this solution on YOUR website!
Question:
A recent Wall Street Journal article indicated that 38% of American teenagers use Pandora's online radio service. Suppose a sample of 25 American teenagers are selected. Use this excel output for this binomial problem(https://gyazo.com/0e2c361c443a8e1aa0da1c0dccc2264e)
1.Find the probability that the number of American teenagers who use Pandora's online radio service differs by greater than 2 from the mean.(round answer to 4 decimal places)
2.Find the probability that more than 35% but at most 70% of these American teenagers use Pandora's online radio service.(round 4 decimal places)
Solution:
n=25
p=0.38
mean=np=9.5
1.
Number within 2 or less from the mean are 8, 9, 10 and 11.
P(outside limit) [0-7, 12-25]
=1-P(within limit)
=1-(P(8)+P(9)+P(10)+P(11))
=1-(0.13899+0.16091+0.15780+0.13188)
=0.41042
2.
lower limit: 35% of 25=8.75 => 9
upper limit: 70% of 25=17.5 =>17
So probability is
P(9 <= X <= 17)= Σ P(i) for i=9,10,11...17
=0.16091+0.15780+0.13188+0.09430+0.05778+0.03036+0.01365+0.00523+0.00170
=0.65362
PS sorry, I do not open attached files.
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