[R] How to make a figure plotting p-values by range of different adjustment values?

Kirsten Morehouse kmoreho1 at swarthmore.edu
Wed Jul 12 16:53:30 CEST 2017

Hi all,

Thank you for taking the time to read my message. I'm trying to make a
figure that plots p-values by a range of different adjustment values.

(Using the **logit** function in package **car**)

My Statistical analyses were conducted on probability estimates ranging
from 0% to 100%. As it's not ideal to run linear models on percentages that
are bounded between 0 and 1, these estimates were logit transformed.

However, this introduces a researcher degree of freedom. In Package
**Car**, the logit transformation code is

        logit(p = doc$value, adjust = 0.025)

    logit definition/Description

    Compute the logit transformation of proportions or percentages.


         logit(p, percents=range.p[2] > 1, adjust)


    p  a numeric vector or array of proportions or percentages.
    percents TRUE for percentages.
    adjust   adjustment factor to avoid proportions of 0 or 1; defaults to
0 if there are no such proportions in the data, and to .025 if there are.)

I chose the default adjustment factor of .025, but I need to determine at
what point my values are greater than .05 to show I did not choose an
ajustment value that makes my results significant.

Ultimately, I want to find the range of adjustment factors do we get P <
0.05?And at what point do we get P > 0.05?

    ## The final product I'm looking for is a figure with the following
      ## 1) Adjustment factor on the x-axis
      ## 2) P value on the y-axis

    Does anyone know how to do this? Thank you so much in advance.

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