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Question

anonymous · Answer

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anonymous · Answer

Once you calculate the mean of the sample:$$\bar x$$The standard deviation you have to use is:$$SD=\sqrt{\frac{ \sum_{k=1}^{n}\left( x_k- \bar x \right)^2 }{ n-1 }}$$Where n=12.
Also, take into account that to build the CI you need to use t-distribution, two-tails and n-1=11 degrees of freedom.

Reason for the calculation of SD using n-1 in the denominator and t-distribution with n-1 degrees of freedom is because sample size is <30

anonymous · Answer

i can't read that formula :(

anonymous · Answer

is it a computer problem or a problem of yours?

anonymous · Answer

you mean where i got the question from?

anonymous · Answer

no, the fact that you can´t read the formula is because it does not appear on your screen or because you dont understand it?

anonymous · Answer

i don't understand it.

anonymous · Answer

you have asked for a formula and it is what it is. Little to explain in the definition of Standard Deviation for small size samples