Stats homework please help

Question

(a) Testing:Your sample consists of 50 subjects, with a mean of 41 and standard deviation of 4.15.Calculate the standardized test statistic, rounded to 2 decimal places.

(b) Testing:

Your sample consists of 20 subjects, with a mean of 57.7 and a sample standard deviation (s) of 3.42.

Calculate the standardized test statistic, rounded to 2 decimal places.

Answer 1

a) H_o: μ = 41.1 and H_A: μ ≠ 41.1

z = (X - μ) / (σ/√n) = (41 - 41.1) / (4.15/√50) = -0.10/0.5869 = -0.17

b) H_o: μ ≤ 59.2 and H_A: μ > 59.2

z = (X - μ) / (σ/√n) = (57.7 - 59.2) / (3.42/√20) = -1.5/0.7647 = -1.96