topic Re: Random Sampling in Data Management Questions https://community.esri.com/t5/data-management-questions/random-sampling/m-p/219769#M12515 <HTML><HEAD></HEAD><BODY><SPAN>That's not a random sample -- that's a systematic sample. For a random sample you'd need </SPAN><BR /><SPAN>to know the actual IDs to highlight them, but for a systematic sample you just need to know</SPAN><BR /><SPAN>the modulus operator for your database and the selection starting point, then you can select </SPAN><BR /><SPAN>using a WHERE clause, e.g., WHERE mod(id,9) = 1. Keep in mind that the range of a modulus</SPAN><BR /><SPAN>is [0..N-1], so mod(9,9) = 0.&nbsp; </SPAN><BR /><SPAN> </SPAN><BR /><SPAN>- V</SPAN><BR /><SPAN> </SPAN><BR /><SPAN>PS: SQL-Server doesn't have a "mod" function, but it has an operator (e.g., WHERE id % 9 = 1)</SPAN></BODY></HTML> Fri, 03 Dec 2010 11:00:56 GMT VinceAngelo 2010-12-03T11:00:56Z Random Sampling https://community.esri.com/t5/data-management-questions/random-sampling/m-p/219768#M12514 <HTML><HEAD></HEAD><BODY><SPAN>Hello,</SPAN><BR /><BR /><SPAN>I have an attribute table with a list of IDs that extends to 8000+.</SPAN><BR /><BR /><SPAN>The study thats being done - has randomly selected households with an interval of 9. </SPAN><BR /><BR /><SPAN>How can I highlight just the selected household IDs on the map ? </SPAN><BR /><BR /><SPAN>Thank you ! </SPAN><BR /><BR /><SPAN>Best,</SPAN><BR /><SPAN>N J A</SPAN></BODY></HTML> Fri, 03 Dec 2010 04:06:37 GMT https://community.esri.com/t5/data-management-questions/random-sampling/m-p/219768#M12514 N_JA 2010-12-03T04:06:37Z Re: Random Sampling https://community.esri.com/t5/data-management-questions/random-sampling/m-p/219769#M12515 <HTML><HEAD></HEAD><BODY><SPAN>That's not a random sample -- that's a systematic sample. For a random sample you'd need </SPAN><BR /><SPAN>to know the actual IDs to highlight them, but for a systematic sample you just need to know</SPAN><BR /><SPAN>the modulus operator for your database and the selection starting point, then you can select </SPAN><BR /><SPAN>using a WHERE clause, e.g., WHERE mod(id,9) = 1. Keep in mind that the range of a modulus</SPAN><BR /><SPAN>is [0..N-1], so mod(9,9) = 0.&nbsp; </SPAN><BR /><SPAN> </SPAN><BR /><SPAN>- V</SPAN><BR /><SPAN> </SPAN><BR /><SPAN>PS: SQL-Server doesn't have a "mod" function, but it has an operator (e.g., WHERE id % 9 = 1)</SPAN></BODY></HTML> Fri, 03 Dec 2010 11:00:56 GMT https://community.esri.com/t5/data-management-questions/random-sampling/m-p/219769#M12515 VinceAngelo 2010-12-03T11:00:56Z