In R and TI-89 you can do

qnorm(prob, mu, sigma) or invNorm(prob, mu, sigma) to get a value of x such that $P(Z < x)$ along a normal curve defined by the specified mean and standard deviation equals prob.

While I could do something like:

Solve[CDF[NormalDistribution[mu, sigma], x] == prob, x]

this is cumbersome.

While I could also use Mathematica's RLink functionality, I would like to know whether there is a native command that does this.

  • 1
    $\begingroup$ You could also use InverseErf, but that's cumbersome too. $\endgroup$ – user484 Jun 12 '15 at 4:32

I think this is the most compact I can get without defining my own function:

InverseCDF[NormalDistribution[mu, sigma], prob]

| improve this answer | |
  • 3
    $\begingroup$ Quantile[NormalDistribution[mu, sigma], prob] saves 2 ;-) $\endgroup$ – ciao Jun 12 '15 at 4:48
  • $\begingroup$ @ciao +1 for teaching me about a new function :D $\endgroup$ – 1110101001 Jun 12 '15 at 4:54
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    $\begingroup$ But why not define q[prob_, mu_, sigma_] := InverseCDF[...]? You'd be using the native command and saving keystrokes. $\endgroup$ – ilian Jun 12 '15 at 5:15

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