class="header-section-number">Chapter 6</span> Activity</h1>
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<p>The objective study of human physical activity is one of the exciting opportunities created by passive EMA <span class="citation">(Marszalek et al., <a href="#ref-Marszalek2014">2014</a>)</span>. Through technological advances in mobile sensing, we are now able to continuously monitor (in-)activity of participants in every-day life, with little to no participant burden.</p>
<p>While questions remain with regard to the validity, reliab