Posted by shelly on Friday, March 26, 2010 at 9:44pm.
The standard deviation is approximately 1/4 the range; therefore, determine the difference between the highest and lowest value in each data set, then divide by 4. This is a rough estimate, but if you actually calculate the standard deviation and it's way off the estimate, then you may need to redo your calculations.
I hope this will help get you started.
Find the standard deviation using the rule of thumb for each of the data sets
57,61,57,57,58,57,61
61,52,69,64,46,54,47
first 7 is 1
second 7 is 5.75