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People were polled on how many books they read the previous year. How many subjects are needed to estimate the number of books read the previous year within one book with 90% c
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People were polled on how many books they read the previous year. How many subjects are needed to estimate the number of books read the previous year within one book with 90% c
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Question 1044665:
People were polled on how many books they read the previous year. How many subjects are needed to estimate the number of books read the previous year within one book with 90% confidence? Initial survey results indicate that sigma
equals 14.2 books. Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! 90% confidence has a z=1.645
the standard error is sigma/sqrt(n). Their product is the interval.
z*sigma/sqrt(n)=SE=1.645*14.2/sqrt (n)=23.359/sqrt(n)=1
Therefore, multiplying both sides by sqrt(n), 23.359=sqrt(n)
square both sides and n=545.64 or 546
