Question 1087491
This requires more information.
The CI is the mean +/- t df=n-1, 0.975 *s/sqrt (n)
The t for the first would be 11 degrees of freedom and under the 0.975 column. The mean and standard deviation are both required, and it would be the sqrt (12).
For 3, use df=3, 0.995 column and sqrt (4).