Aschool is preparing the schedule of classes for the next academic year. they are concerned about scheduling calculus, physics, english, statistics, economics, chemistry, and german classes, planning to offer a single section of each one. below are the lists of courses that each of six students must take in order to successfully graduate. determine the smallest number of class periods that can be used to schedule these courses if each student can take at most one course per class period. explain why fewer class periods cannot be used.
student courses

1 chemistry, physics, economics

2 english, german, statistics

3 statistics, calculus, german

4 chemistry, physics

5 english, chemistry

6 chemistry, economics

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