Find the interval [μ - z (σ/sqrt(n)), μ + z (σ/sqrt(n))] within which 95 percent of the sample means would be expected to fall, assuming that each sample is from a normal population.
a. μ = 173, σ = 20, n = 42.
b. μ = 874, σ = 12, n = 7.
c. μ = 76, σ = 2, n = 26.
