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Re: how to convert p value of <.0001 to actual number

Hi MS, could you provide the example for this ANOVA value, I'm just curious how much I can force JMP to show those values Thanks!

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ms
Super User ms
Super User

Re: how to convert p value of <.0001 to actual number

Here's an example. If I push it a little further, e.g. by decreasing the std dev, the ANOVA p-value will show as "0". For Dunnett's method, low p-values are less accurate. They appear to show as "0" if lower than about 1e-15.

 

 

dt = New Table("test", add rows(2e3), New Column("X", character), New Column("Y", numeric));
For Each Row(
    If(Row() > 1e3,
        :X = "B";
        :Y = Random Normal(0, 50);
    ,
        :X = "A";
        :Y = Random Normal(1e2, 50);
    )
);

dt << Oneway(
    Y(:Y),
    X(:X),
    With Control(1, {"A"}),
    Means(1),
    SendToReport(
        Dispatch({"Oneway Anova", "Analysis of Variance"}, "Prob > F", NumberColBox, {Set Format("Best", 12)}),
        Dispatch(
            {"Means Comparisons", "Comparisons with a control using Dunnett's Method", "LSD Threshold Matrix"},
            "p-Value",
            NumberColBox,
            {Set Format("Best", 12)}
        )
    )

);

 

 

Prob > F

6,90185e-311

 

p-Value

1

0

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Steven_Moore
Super User

Re: how to convert p value of <.0001 to actual number

jaboraws,

JMP uses a value called Log Worth in the Partition platform to convert very small p-values into useable numbers.  You might want to look at that.

The Log Wroth is the -log10(p-value).

Hope this helps.

Steve
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jaboraws
Level I

Re: how to convert p value of <.0001 to actual number

This is exactly what I am trying to do.  I performed a Fit Y by X and then performed a Dunn's test to compare the means of my samples versus my control group and got a list of p values (which I ultimately want to convert to -log10(pvalues)).

The problem is the list of p values contains many "<.0001" values which are not usable for calculating the log worth.  I am trying to look into the log worth calculation in the partition but not having much luck yet.,

Thank you for the information.,

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Re: how to convert p value of <.0001 to actual number

Question, can you share the data privately, so I could take an explicit look on it? Guess it is at least too confidential to share it here, but if you want me to try to replicate what you experience, I'm happy to take a look.

just email to martin.demel@jmp.com

... and the steps you did

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rlw268
Level II

Re: how to convert p value of <.0001 to actual number

Did you ever find an answer for this? I am using logistic regression one of my x variables has a p-value of 0.00001 and logworth 56.125, and the other has a p-value of 0.00219 and logworh of 2.something. I know JMP is taking the negative log of the p value but that does not work for p-values of 0. I am lost?

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Re: how to convert p value of <.0001 to actual number

You can double-click the p-value, change the format to Best, and change the Width so that you can see the whole number, for example, Width = 15.

Learn it once, use it forever!
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