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Lady_Fox [76]
3 years ago
15

A study of one thousand teens found that the number of hours they spend on social networking sites each week is normally distrib

uted with a mean of 30 hours. The population standard deviation is 2 hours. What is the 95% confidence interval for the mean?
Mathematics
1 answer:
Svetradugi [14.3K]3 years ago
3 0

Given:

Sample Mean <span>= 30<span>
Sample size </span><span><span><span>= 1000</span></span><span>
</span></span></span>Population Standard deviation or <span><span><span>σ<span>=2</span></span><span>
</span></span>Confidence interval </span><span>= 95%</span>

to compute for the confidence interval

Population Mean or <span>μ<span><span>= sample mean ± (</span>z×<span>SE</span>)</span></span>

<span><span>where:</span></span>

<span><span>SE</span>→</span> Standard Error

<span><span>SE</span>=<span>σ<span>√n</span>= 30</span></span>√1000=0.9486

Critical Value of z for 95% confidence interval <span>=1.96</span>

<span>μ<span>=30±<span>(1.96×0.9486)</span></span><span>
</span></span><span>μ<span>=30±1.8594</span></span>

Upper Limit

<span>μ <span>= 30 + 1.8594 = 31.8594</span></span>

Lower Limit

<span>μ <span>= 30 − 1.8594 = <span>28.1406</span></span></span>

<span><span><span>
</span></span></span>

<span><span><span>answer: 28.1406<u<31.8594</span></span></span>

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