import math
def z_confidence_interval(sample_mean, pop_std, n, z_crit=1.96):
margin = z_crit * (pop_std / math.sqrt(n))
return sample_mean - margin, sample_mean + margin
lower, upper = z_confidence_interval(sample_mean=72.5, pop_std=9.0, n=50)
print("95% CI:", (round(lower, 2), round(upper, 2)))