an><span class="fl">1871</span><span class="op">:</span><span class="fl">1970</span>, <span class="va">fit</span><span class="op">$</span><span class="va">smoothed</span><span class="op">$</span><span class="va">level</span> <span class="op">-</span> <span class="fu"><a href="https://rdrr.io/r/stats/Normal.html" class="external-link">qnorm</a></span><span class="op">(</span><span class="fl">0.95</span><span class="op">)</span> <span class="op">*</span> <span class="fu"><a href="https://rdrr.io/r/base/MathFu