Posted by Ayuda!!! on .
Find the value of zα/2 to construct a confidence interval with level:
a. 95%
b. 98%

statistics 
PsyDAG,
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions (.025 & .01, respectively) that relate to the Z scores.
95% interval = mean ± 1.96 SD, so Z = 1.96.
You do the second one. 
statistics 
Ayuda!!!,
I got it! the second one is Z = 2.326
Thanks!!! :)