Question

17,14,6,10,11

Answer 1

mean or average = (17+14+6+10+11)/5 = 11.6

now take differences:
17 - 11.6 = 5.4 , square it ----> 29.16
.....
11 - 11.6 = -.6 ,square it ----> .36

add up all those squares ......
now look up which version of standard deviation your text uses, so
either divide by 5 or by 4, ...
take the square root <---- your sd
look up how your text defines variance, usually it is (sd)^2