QMS 202 Lecture Notes - Lecture 4: Confidence Interval, Null Hypothesis, Test Statistic
Document Summary
If the population standard deviation is unknown, we use the sample standard deviation, s. Because of this we use the t distribution instead of the z distribution to test the null hypothesis. When using the t distribution we assume the population we are sampling is normal distribution. All other steps, concepts and conclusions are the same. Convert sample stat (cid:454) to a t stat test statistic. Since this is a t test, we cannot calculate the p value without a calculators. If the p value> a, do not reject h0. If the confidence interval contains the hypothesized mean, we do not reject h0. If the interval does not contain the hypothesized mean we reject h0. Can differ according to the confidence level. Use level of significance given if not assume a=0. 05. F5 dist, f2 t, f3 invt if area (probability) is given. Left tail/ right tail can use symmetry and flip the sign for either size.