Like the Sharp EL-520W<\/a>, the Casio fx-260Solar requires you to set the mode to use its standard deviation function. On the Casio, it’s MODE<\/span> .<\/span> (mode, then decimal point). What I like is that the Casio has the modes printed just under the screen. Look and you’ll see, in blue, . SD<\/span>. Of course, SD refers to Standard Deviation.<\/p>\n Example: Calculate the standard deviation of the number set {-18,16,0,45,100,32,27}.<\/strong><\/p>\n Solution:<\/strong> As mentioned above, key in MODE<\/span> .<\/span> to get in SD mode. Then, you should see SD in the upper right corner.<\/p>\n To enter the numbers, you use the M+ key at the bottom right. In SD mode, it becomes the DATA<\/span> key. Look underneath it; you’ll see DATA<\/span> printed in blue.<\/p>\n To input -18, you actually have to enter 18 first, then<\/em> +\/-<\/span>. Reason: the Casio fx-260Solar is reverse-entry.<\/p>\n Input -18 M+<\/span>, 16 M+<\/span> and so on. Unlike the Sharp EL-520W<\/a>, the Casio fx-260Solar does not give you feedback as it accepts the data.<\/p>\n Reaching the end of our list, we key in 27 M+<\/span>. It’s time to find the standard deviation. Key in SHIFT<\/span> 8<\/span> to get \u03c3n<\/sub>. You should get 34.9, which is of course what we got with the Sharp EL-520W<\/a>. After all, the data set is the same. To get \u03c3n-1<\/sub>, key in SHIFT<\/span> 9<\/span>. I believe that Foundations 11 prefers \u03c3n<\/sub>.<\/p>\n To clear the statistical data before entering a new list, change the mode to COMP by pressing MODE<\/span> 0<\/span>, then press MODE<\/span> .<\/span> to get back into SD mode. Changing out of SD mode, then back into it, seems to clear the previous list.<\/p>\n The mode for ordinary use is COMP. Once again: to return to COMP mode, press MODE<\/span> 0<\/span><\/p>\n