SOLUTION: A city is interested in estimating the amount of time children spend on the internet each day. It is known the the time spent follows a normal distribution with standard deviat

Question 927356: A city is interested in estimating the amount of time children spend on the internet
each day. It is known the the time spent follows a normal distribution with standard
deviation 35 minutes.
(a) How many children would be needed to estimate the true mean amount of time
spent on the internet to within 19 minutes with 95% confidence?
(b) How many children would be needed to estimate the true mean amount of time
spent on the internet to within 19 minutes with 96% confidence?
(c) Only using your answer in (a), how many children are needed to estimate the
true mean amount of time spent on the internet to within 18 minutes with 95%
confidence?
(d) What happened to your sample size from part (a) to part (b)? Explain.
(e) Create a 90% confidence interval for the true mean amount of time spent on the
internet.
(f) Interpret your interval in (e).

Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!
a) n = (zSD/ME)^2 = (1.96*35/19)^2 = 13.0359 0r 14
b) n = (zSD/ME)^2 = (2.0537*35/19)^2 = 14.312 0r 15
c) n > 14, n = (zSD/ME)^2 = (1.96*35/18)^2 = 14.5246 0r 15
d) Sample size part b is Larger due to increased confidence Level.
e) ME = 1.645(12) = 57.575 (round as directed)

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