The mean of a sample is a) Always equal to the mean of the population b) Always smaller than the mean of the population c) Computed by summing the data values and dividing the sum by (n -1) d) Computed by summing all the data values and dividing the sum by the number of items e) None of the above answers is correct. #11 Since the mode is the most frequently occurring data value, it a) Can never be larger than the mean b) Is always larger than the median c) Is always larger than the mearn d) Must have a value of at least two e) None of the above answers is correct. #12. The difference between the largest and the smallest data values is the a) Variance b) Interquartile range c) Range d) Coefficient of variation e) None of the above answers is correct. #18 Let X and Y be independent random variables with Calculate E (X+1) (Y-1) 1 a) 1 b) 9/2 c) 16 d) 17 e) 27 f) None of these