CODEWITHSUNDEEP
random
user695652
user695652

Reputation: 4275

Uniform distribution [0,1) converted into {-1,1}

If i have a uniformly distributed random variable in [0,1), how can i modify it (only using arithmetic expressions) s.t. it is -1 with probability 1/2 and 1 with probability 1/2?

Upvotes: 1

Views: 357

Answers (2)

BenH
BenH

Reputation: 2120

If your random variable is less than 0.5, map it to -1, otherwise map it to 1.

Edit: If you allow using absolute value, you can do (x - 0.5) / abs(x - 0.5).

Upvotes: 0

ugoren
ugoren

Reputation: 16441

If floor (or conversion to nearest integer below x) is OK:

floor(x*2)*2-1

With rounding to the nearest integer:

round(x*2-0.5)*2-1

Upvotes: 1

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