 hierarchical structure assuming
fixed effect models, i.e.,
<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>τ</mi><mo>∼</mo><mi>f</mi><mo stretchy="false" form="prefix">(</mo><mi>.</mi><mo stretchy="false" form="postfix">)</mo></mrow><annotation encoding="application/x-tex">\tau \sim f(.)</annotation></semantics></math>
and
<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>ρ</mi><mo>=</mo><mn>1</mn></mrow><annotation encoding="a