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Subsampling estimates of the Lasso distribution.

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60 Numerical results<br />

Figure 6.3: <strong>Subsampling</strong> confidence intervals for single scenarios <strong>of</strong> <strong>the</strong> models C and C’<br />

(n= 250). Red triangles stand for <strong>the</strong> true parameters.<br />

Definition 6.1.3.2. Suppose that for a random variable X and an hypo<strong>the</strong>sis H, one has<br />

a familiy {S α (X); α ∈ (0, 1)} <strong>of</strong> rejection regions satisfying<br />

S α ⊂ S α ′<br />

whenever α < α ′ . Then a p-value is defined as<br />

ˆp = ˆp(X) = inf{α : X ∈ S α }<br />

that is, <strong>the</strong> smallest significance level at which one would reject <strong>the</strong> hypo<strong>the</strong>sis H.<br />

Given p-values ˆp 1 , . . . , ˆp s associated to hypo<strong>the</strong>sis tests H 1 , . . . , H s , <strong>the</strong> Holm procedure<br />

consits int he following steps:<br />

1. Consider <strong>the</strong> ordered realized p-values ˆp (1) ≤ . . . , ˆp (s) and <strong>the</strong> corresponding hypo<strong>the</strong>ses<br />

H (1) , . . . , H (s) .<br />

2. If ˆp (1) ≥ α/s, accept H 1 , ·, H s and stop. If ˆp (1) < α/s reject H (1) and test <strong>the</strong> remaining<br />

s − 1 hypo<strong>the</strong>ses at level α/(s − 1).

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