SOLUTION: Visits to Networking Sites A sample of 10 networking sites for a specific month has a mean of 26.1 and a standard deviation of 4.2. Find the 99% confidence interval of the tru

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Question 1203121: Visits to Networking Sites A sample of 10 networking
sites for a specific month has a mean of 26.1 and a
standard deviation of 4.2. Find the 99% confidence
interval of the true mean.

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

The sample mean symbol is x̄, pronounced “x bar”.
+n=10
​

x̄=+26.1
+s=4.2
​
Two-sided confidence interval CI :

​++df=n-1=10-1=9
++alpha=1-0.99=0.01
++Z%5Bc_%28alpha%2F2%29%5D=Z%5Bc%280.005%29%5D=3.2498=3.25


+CI= (x̄-+Z%5Bc%5D%2As%2Fsqrt%28n%29, x̄++Z%5Bc%5D%2As%2Fsqrt%28n%29)

CI= (26.1-%283.25%2A4.2%29%2Fsqrt%2810%29,+26.1%2B%283.25%2A4.2%29%2Fsqrt%2810%29)

CI= (26.1-4.3, 26.1%2B4.3)

CI= (21.8, 30.4)


99% confidence interval:

21.8+%3CCI+%3C+30.4