18.05 Study Guide - Midterm Guide: Mit Opencourseware
Document Summary
To practice for the exam use the t and z-tables supplied at the end of this le. Be sure to learn to use these tables. Note the t and z-tables give left tail probabilities and the 2-table gives right tail critical values: (a) we compute the data mean and variance x = 65, s2 = 35. 778. The number of degrees of freedom is 9. We look up the critical value t9,0. 025 = 2. 262 in the t-table. The 95% con dence interval is t9,0. 025s t9,0. 025s x n. On the exam you will be expected to be able to use the t-table. We won"t ask you to compute by hand the mean and variance of 10 numbers. 95% con dence means that in 95% of experiments the random interval will contain the true . It is not the probability that is in the given interval.
