Conﬁdence intervals

Khan Academy:
 * 1) Confidence Interval 1
 * 2) Confidence Interval Example
 * 3) Small Sample Size Confidence Intervals
 * 4) T-Statistic Confidence Interval
 * 5) Confidence Interval of Difference of Means
 * 6) Clarification of Confidence Interval of Difference of Means