## A.2 STUDENT'S *T*-DISTRIBUTION

Critical values of t are shown in Table A.2 for various degrees of freedom *(df)* The area or probability values (α) to the right of the *t-value* (see Figure A.2) are shown in the table. For example, with 13 degrees of freedom and 0.025 probability (α) the *t-value* would be 2.160.

**Figure A.1.** Area to the right of the *z-score*

**Table A.1.** Standard normal distribution

**Table A.2.** Student's t-distribution

**Figure A.2.** Area to the right of the *t-value*