We consider the identity testing problem - or goodness-of-fit testing problem
- in multivariate binomial families, multivariate Poisson families and
multinomial distributions. Given a known distribution p and n iid samples
drawn from an unknown distribution q, we investigate how large ρ>0
should be to distinguish, with high probability, the case p=q from the case
d(p,q)≥ρ, where d denotes a specific distance over probability
distributions. We answer this question in the case of a family of different
distances: d(p,q)=∥p−q∥t for t∈[1,2] where ∥⋅∥t is the
entrywise ℓt norm. Besides being locally minimax-optimal - i.e.
characterizing the detection threshold in dependence of the known matrix p -
our tests have simple expressions and are easily implementable.