RightAid Inc $\mu$ ₁ = $\mu$ ₂ = $\mu$ ₃
B)

RightAid Inc.operates a regional chain of 120 pharmacies.Each pharmacy's floor plan includes a greeting card department which is relatively isolated.Cathy Eng, Marketing Manager, feels that the level of lighting in the greeting card department may affect sales in that department.She chooses three levels of lighting (soft, medium, and bright) and randomly assigns six pharmacies to each lighting level.Cathy's null hypothesis is ___.

A) $\mu$ ₁ = $\mu$ ₂ = $\mu$ ₃
B) $\mu$ ₁ $\neq$ $\mu$ ₂ $\neq$ $\mu$ ₃
C) $\mu$ ₁ $\ge$$\mu$ ₂ $\ge$ $\mu$ ₃
D) $\mu$ ₁ $\le$$\mu$ ₂ $\le$$\mu$ ₃
E) $\mu$ ₁ $\le$$\mu$ ₂ ≥ ₃