http://forum.lowyat.net/ Sun, 12 Jul 2026 22:57:08 +0800 FeedCreator 1.7.2 http://forum.lowyat.net/topic/4217887 Hi.<br /><br />As we all know, a random variable X that is normally distributed can be written as X ~ N(25,16), for example, where the mean is 25 and the variance is 16. 25 and 16 are the parameters.<br /><br />In order to standardize X to Z, the formula used is (X - mean)/standard deviation.<br /><br />So, my question is: Why is variance the parameter, instead of standard deviation, since we use standard deviation in the standardization? watdatlinna Education Essentials Thu, 09 Mar 2017 09:31:40 +0800 http://forum.lowyat.net/topic/4177042 For a class interval of 0 - 4, what is the lower boundary? <span style='font-size:16pt;line-height:100%'>- 0.5 or just 0</span>? What is your reason behind it?<br /><br />Thank you in advance. watdatlinna Education Essentials Tue, 17 Jan 2017 10:04:13 +0800