1. 1 The t table provides critical value for various probabilities of interest. The form of the probabilities that appear in Appendix B are: P(t > t A, d.f. ) = A That is, for a given degree of freedom, and for a predetermined right hand tail probability A, the entry in the table is the corresponding t A. These values are used in computing confidence interval estimates and performing hypotheses tests. Probability calculations for the t distribution

2. 2 A, df t.05,20 =? t.100 t.05 t.025 t.01 t.005 Let A=.05 Using the t-table t The degrees of freedom define the specific t-distribution in question. The area ‘A’ is the right hand tail probability. And let df =

3. 3 t.100 t.05 t.025 t.01 t.005 A=.05 Using the t-table -t.05,20 = - 1.725 Because the t-distribution is symmetrical around zero, the t value is for a left right hand probability of ‘A’ is -t df,A

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