Consider the procedure described in Section 7.3 for estimating average delay d _i . Suppose that u = 0.1. Let r ₁ – t ₁ be the most recent sample delay, let r ₂ – t ₂ be the next most recent sample delay, and so on.

a. For a given audio application suppose four packets have arrived at the receiver with sample delays r ₄ – t ₄ , r ₃ – t ₃ , r ₂ – t ₂ , and r ₁ – t ₁  Express the estimate of delay d in terms of the four samples.

b. Generalize your formula for n sample delays.

c. For the formula in Part b, let n approach infinity and give the resulting formula. Comment on why this averaging procedure is called an exponen-tial moving average.