The Cambridge Power and Light Company selected a random sample of 20 residential customers. Following are the amounts, to the nearest dollar, the customers were charged for electrical service last month:
53 49 54 50 21 46 75 45 63 76 61 63 36 34 54 63 37 62 66 62
(a) Compute the arithmetic mean.(Round your answer to 2 decimal places. Omit the "$" sign in your response.)
The mean is $
(b) Indicate whether it is a statistic or a parameter.