For metal, calculate the average rate of change between 1980 and 1988. Then interpret what this value means. a. From 1980 to 1988, the number of pounds of metal per person per day decreased by 0.00125 per year. c. From 1980 to 1988, the number of pounds of metal per person per day decreased by 0.125 per year. b. From 1980 to 1988, the number of pounds of metal per person per day decreased by 0.071 per year. d. From 1980 to 1988, the number of pounds of metal per person per day increased by 0.01 per year.

Each of the following data sets has a mean of x = 10. (i) 8 9 10 11 12 (ii) 7 9 10 11 13 (iii) 7 8 10 12 13 (a) without doing any computations, order the data sets according to increasing value of standard deviations. (i), (iii), (ii) (ii), (i), (iii) (iii), (i), (ii) (iii), (ii), (i) (i), (ii), (iii) (ii), (iii), (i) (b) why do you expect the difference in standard deviations between data sets (i) and (ii) to be greater than the difference in standard deviations between data sets (ii) and (iii)? hint: consider how much the data in the respective sets differ from the mean. the data change between data sets (i) and (ii) increased the squared difference îł(x - x)2 by more than data sets (ii) and (iii). the data change between data sets (ii) and (iii) increased the squared difference îł(x - x)2 by more than data sets (i) and (ii). the data change between data sets (i) and (ii) decreased the squared difference îł(x - x)2 by more than data sets (ii) and (iii). none of the above