https://community.jmp.com/t5/Discussions/Any-formula-or-script-to-combine-standard-deviation-of-different/m-p/678434#M86476 <P>Hi all,<BR /><BR />Currently, I was stuck to combining standard deviation from different group into one standard deviation.<BR />For example<BR />A) sample = 50, mean = 5, standard deviation = 3</P><P>B) sample = 40, mean = 6, standard deviation =2</P><P>C) sample = 20, mean = 7, standard deviation =4</P><P>How I can combine standard deviation from 3 groups into one. Is there any function available in JMP to support this?<BR />Thank a lot&nbsp;</P> Sat, 16 Sep 2023 13:36:58 GMT PhamBao 2023-09-16T13:36:58Z https://community.jmp.com/t5/Discussions/Any-formula-or-script-to-combine-standard-deviation-of-different/m-p/678434#M86476 <P>Hi all,<BR /><BR />Currently, I was stuck to combining standard deviation from different group into one standard deviation.<BR />For example<BR />A) sample = 50, mean = 5, standard deviation = 3</P><P>B) sample = 40, mean = 6, standard deviation =2</P><P>C) sample = 20, mean = 7, standard deviation =4</P><P>How I can combine standard deviation from 3 groups into one. Is there any function available in JMP to support this?<BR />Thank a lot&nbsp;</P> Sat, 16 Sep 2023 13:36:58 GMT https://community.jmp.com/t5/Discussions/Any-formula-or-script-to-combine-standard-deviation-of-different/m-p/678434#M86476 PhamBao 2023-09-16T13:36:58Z https://community.jmp.com/t5/Discussions/Any-formula-or-script-to-combine-standard-deviation-of-different/m-p/678447#M86477 <P>Variances add, standard deviations do not.&nbsp; Square the standard deviations, add them, take the average.&nbsp; Then take the root.</P> Sat, 16 Sep 2023 13:47:08 GMT https://community.jmp.com/t5/Discussions/Any-formula-or-script-to-combine-standard-deviation-of-different/m-p/678447#M86477 statman 2023-09-16T13:47:08Z