<p>I posted <a href="https://softwarerecs.stackexchange.com/questions/52728/searching-for-a-rhythm-in-weight-loss-gain">this question</a> on Software Recommendations. As it is getting no response, I think that I might try to make a meaningful chart for my friend, in Excel .</p>

<p>Actually, I would prefer someone else to post an Excel formula to do so, but that is certainly off-topic here.</p>

<p>What I am hoping is not off topic is asking for a mathematical formula which will produce meaningful results.</p>

<p>From that question:</p>

<blockquote>
  <p>Basically my friend weighs daily and has historical data in CSV format. They would like a gratis app that takes that data and overlays it in some form of weekly chart. E.g shows only Monday to Sunday (start day preferably selectable), not several months or years.  </p>
  
  <p>We are unsure what format the display should take, but the objective is to see if there is a pattern to weight loss/gain on certain days of the week.  </p>
  
  <p>My friend has been steadily losing weight for months now, but against that background, there are days when weight is gained and my friend is looking for an identifiable pattern. A very obvious example would be weight gain on Monday after a weekend binge, but this is not the case, just an example.   </p>
  
  <p>The idea is that if certain days can be identified as problematic then the cause can be identified and behavio(u)r changed.</p>
</blockquote>

<p>So, could I somehow phrase that to be an on-topic question here? I am looking for a pattern in data (and how best to represent it visually).</p>
