Even though the population standard deviation is unknown, an investigator uses z rather than the more appropriate t to test a hypothesis at the .05 level of significance.

(a) Is the true level of significance larger or smaller than .05
(b) Is the true critical value larger or smaller than that for the critical z?

a) The level of significance is large because here z is not appropriate.

b) The true critical value is larger than z because the level of significance is large.

Step-by-step explanation:

a) Based on the question under consideration, the true level of significance is larger than .05 level of significance is large, the reason being that z is not appropriate in this case.

b) The true critical value is larger than that of the critical z, this is because the level of significance is large.

t* in P(T > t*) = 0.975 is more than z* = 1.96 in P(z> z*) =0.975