4. (25 points) The National Infomercial Marketing Association conducted a survey among buyers of a particular product. and the results are shown in the table below, where x represent the number of times buyers of a product had watched a TV infomercial before purchasing the product, and p(x) the probability that buyers purchase the product after watching it at times. Values of 5 or more for it were treated as 5. x ' 1306) l i 0.27 2 3 i108 4 0.09 5 0.15 (a) Complete the missing probability. (b) What is the probability that buyers watch three or fewer infomercials before purchasing the product? Answer: The probability is i:i (c) Compute the expected value of this distribution. Answer: The expected value is ,u = i:i (d) Compute the stande deviation of this distribution