gluon wrote:
Is the standard deviation of the salaries of Company Y’s employees greater than the standard deviation of the salaries of Company Z’s employees?
(1) The average (arithmetic mean) salary of Company Y’s employees is greater than the average salary of Company Z’s employees.
(2) The median salary of Company Y’s employees is greater than the median salary of Company Z’s employees.
E.
Std Deviation is essentially the distance from the mean. It can also be somewhat thought of as the spread between the various numbers.
Ex/ 1,2,3,4,5. Mean is 3, and so is the median. STD is equal to 1.
There is a very tedious method to figure out the std deviation, buts its unlikely ul be tested on it.
For S1: this doesnt tell us the std dev's are different.
S2: same thing.
For both and for either statement you can make up two sets:
Set Y and Set Z
Y: 2,3,4,5,6
Z: 1,2,3,4,5. Both mean and median are greater in set Y. But std deviation is the same.
You can create many sets where the std D is different.