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GO Classes GATE DA | GOAT DPP Series | Machine Learning | DAY 4 | Question: 2

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Consider a least-squares linear regression problem with $X \in \mathbb{R}^{n \times d}$ and $y \in \mathbb{R}^n$. If the least-squares solution is unique, which of the following must be true?

  1. $\operatorname{rank}(X)<d$
     
  2. $\operatorname{rank}(X)=d$
     
  3. $n<d$
     
  4. $d>n$
     

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