Question 1069517: Nine randomly selected teens were asked how many hours per day they spend interacting with others through social media, such as Instagram and Snapchat. The mean time was 4.8 hours and the standard deviation was 1.4 hours. Find the 90% confidence interval for the mean time. Assume this variable is normally distributed.
a (3.931, 6.668)
b (3.932, 5.668)
c (2.932, 5.568)
d (3.293, 5.569)
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! This is a t-interval with t df=8 0.95=1.86, mean 4.8 and s=1.4
t*s/sqrt(n)=1.86*1.4/3=0.868
Add and subtract this value to the mean to get the interval
(3.932, 5.668)
B.
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