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Re: Quantile function

• To: mathgroup at smc.vnet.net
• Subject: [mg35374] Re: [mg35316] Quantile function
• From: BobHanlon at aol.com
• Date: Wed, 10 Jul 2002 02:19:39 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

In a message dated 7/8/02 3:37:12 AM, a at a.a writes:

>When using the quantile function:
>
>In[7]:=
>Quantile[dist, 0.8]
>
>Out[7]=
>0.841621
>
>can anyone tell me how to get more accuracy?
>

Needs["Statistics`NormalDistribution`"]

dist = NormalDistribution[0, 1];

Quantile[dist, 0.8]

0.841621

The display is truncated for output.  The InputForm shows this.

Quantile[dist, 0.8] // InputForm

0.8416212335729144

NumberForm will display additional digits but only up to the maximum 
consistent with machine precision.

NumberForm[Quantile[dist, 0.8], 20]

0.841621233572914

For precision beyond machine precision you need to use exact or higher 
precision numbers in the definition of the distribution (as above) and in 
the call to Quantile.

N[Quantile[dist, 8/10], 20]

0.84162123357291420518

Quantile[dist, N[8/10, 20]]

0.84162123357291420518


Bob Hanlon
Chantilly, VA  USA