, 3, <span class="ValueType">double</span>.NaN, 4, 5, 6 };     <br />&#160;&#160;&#160; Assert.IsNaN(array.Average());     <br />} </div>  <p>I&#39;m sure someone can think of some other interesting scenarios I should be considering :)</p>  <h3>Let&#39;s implement it!</h3>  <p>This is another cut-and-paste job, but with more editing required - for each method, I needed to make sure I was using the right accumulator type, and I occasionally removed redundant casts. Still, the code follows pretty much the sam