A study of one thousand teens found that the number of hours they spend on social networking sites each week normally distributed with a mean of 15 hours. The population standard deviation is 2 hours. What is the 95% confidence interval for the mean?

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Sep 6, 2016

Answer:

Population Mean lies between #15.0294# and #14.9706#

Explanation:

Given -

Sample Mean #barx=15#
Sample size #n=1000#
Population SD #sigma=2#
Confidence interval #= 95%#

Population Mean #mu=barx+-(z xx SE)#

#SE -># Standard Error

#SE=sigma/sqrtn=15/1000=0.015#

Critical Value of #z# for 95% confidence interval #=1.96#

#mu=15+-(1.96 xx 0.015)#
#mu=15+-0.0294#

Upper Limit

#mu=15+0.0294=15.0294#

Lower Limit

#mu=15-0.0294=14.9706#

Look at the Diagram

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