Do One of the Following, as Appropriate: (A) Find the Critical

Multiple Choice

Do one of the following, as appropriate: (a) Find the critical value $z_{?/2}$ , (b) find the critical value $t_{?/2}$ , (c) state that neither the normal nor the t distribution applies
- $90 \% ; \mathrm { n } = 10 ; \sigma$ is unknown; population appears to be normally distributed.

A) $t _ { \alpha / 2 } = 1.812$
B) $\mathrm { t } _ { \alpha / 2 } = 1.833$
C) $\mathrm { z } _ { \alpha / 2 } = 1.383$
D) $\mathrm { z } _ { \alpha / 2 } = 2.262$