Determine the critical value z ∝/2 that corresponds to the given level of confidence

a) 98%

b) 85%


The ∝/2 is at the right bottom of the z it is not under it or on top of it

Miranda -


a) 98% means 2%/2 = 1% or 0.01 in the tails. Look up this area of 0.01 in a Standard Normal table and you should find the corresponding z-values are +/- 2.326.

b) 85% means 15% / 2 = 7.5% or 0.075 in the tails. Look up this area of 0.075 in a Standard Normal table and you should find the corresponding z-values are +/- 1.440

Hope that helps