Question

Does the amount of hazardous material absorbed by the bodies of hazardous waste workers depend on gender? You want to test the hypotheses that the amount absorbed by men (group 1) is less than the amount absorbed by women (group 2). A random sample of 231 male workers and 197 female workers showed an average lead absorption in the blood of 12.2 (SD = 0.774) and 12.21 (SD = 0.577), respectively (measured in micrograms/deciliter). Assuming that the population standard deviations are the same, perform a two independent samples t-test on the hypotheses Null Hypothesis: μ₁ ≥ μ₂, Alternative Hypothesis: μ₁ < μ₂. What is the test statistic and p-value of this test?

Question 14 options:

	1) Test Statistic: -0.149, P-Value: 0.8816
	2) Test Statistic: 0.149, P-Value: 0.4408
	3) Test Statistic: 0.149, P-Value: 0.5592
	4) Test Statistic: -0.149, P-Value: 0.4408
	5) Test Statistic: -0.149, P-Value: 0.5592

Answer 1

The statistical software output for this problem is:

Two sample T summary hypothesis test: V1 : Mean of Population 1 2 : Mean of Population 2 V1 - H2 : Difference between two means Ho : 11 - 12 = 0 HA: P1 - H2 <0 (with pooled variances) Hypothesis test results: Difference Sample Diff. Std. Err. DF T-Stat P1 - 2 -0.01 0.066953064 426 -0.14935836 P-value 0.4407

Hence,

Test Statistic: -0.149, P-Value: 0.4408

Option 4 is correct.