SOLUTION: A recent news report had found that 68% of all internet searches use Google (a website used for search). Suppose a random sample of 50 searches is taken from a database that conta

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Question 1104729: A recent news report had found that 68% of all internet searches use Google (a
website used for search). Suppose a random sample of 50 searches is taken from a database that contains
records of internet activity and searches.
29. What is the probability that exactly 25 searches are conducted on Google?
30. What is the probability that at least 40 searches are conducted on Google?
31. How likely is it that less than 30 searches are conducted on Google?
32. On average how many searches out of 50 should we expect to be conducted on Google? With what
standard deviation?
33. Would it be unusual for 45 of the searches to be conducted using Google? Explain.
Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website!
29. 50C250.68^25*0.32^25=0.0035
30. Mean is np=34; variance is np(1-p)=34*0.32=10.68; sd=sqrt (var)=3.27. This answers 32.
using continuity correction factor z>(39.5-34)/3.27=1.68. Probability is 0.0465
31. Fewer than 30 is (29.5-34)/3.27 or z<-1.38, probability is 0.0838.
33. For 45, the probability is 50C450.68^45*0.32*5=0.0002. Unusual. The mean is 34 and the sd is 3.27. Most of the probability will involve searches between 31 and 37.