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<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Hello Miso,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">I get asked this question a lot; far too often to be honest.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">You mentioned residuals, so I am assuming your question relates to fitting linear models (of any kind) using the `lm()` function.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">There are four assumptions for the linear model, least important of which is the normality of residuals. It is however the easiest one for sighted people to assess courtesy of the normal quantile
plot.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">A lack of normality is often a symptom that another assumption is also questionable.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Not having the correct model, constant variance, and independence of residuals all have greater impact than the lack of normality.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">You can investigate most assumptions by way of fitting alternative models or making use of various hypothesis tests (variance and independence), not to forget the tests for normality. Many of these
are used in the `UniDesc()` function in the BrailleR package.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Jonathan<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="mso-ligatures:none">From:</span></b><span lang="EN-US" style="mso-ligatures:none"> BlindRUG <blindrug-bounces@nfbnet.org>
<b>On Behalf Of </b>Miso Kwak via BlindRUG<br>
<b>Sent:</b> Monday, November 27, 2023 10:58 AM<br>
<b>To:</b> 'Blind R Users Group' <blindrug@nfbnet.org><br>
<b>Cc:</b> misokwak12@gmail.com<br>
<b>Subject:</b> [BlindRUG] Interpreting QQ Plot nonvisually or alternative approaches<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-US">Hello,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Is there any way to understand a QQ Plot I produce in R nonvisually?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Or is there any comparable alternative that would allow me to make interpretation on the distribution of residuals?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Thank you in advance.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Miso<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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