Math Is Fun Forum

Hi,

Below are some of my data i'm trying to get the warning and control limits for but in order to get them I need the standard deviation. In excel there are some functions like STDEV and STDEVP but they use the same method by working out the mean as 49.9993 and my true value is actually 50.0001. Is there any way I can work this out without hazzle as I do have a lot of data I have to analyze. I would appreciate the help.

49.9993   
49.9993   
49.9994   
49.9996   
49.9995   
49.9994   
49.9992   
49.9995   
49.9995   
49.9990   
49.9990   
49.9997   
49.9991   
49.9991   
49.9993   
49.9991   
49.9991   
49.9992   
49.9995   
49.9990