standard deviation formula

standard deviation formula : Applying this to the original formula for standard deviation gives: \sigma = \ sqrt{\frac{1}{N} \left .....   More from Wikipedia

  Review of what we've learned. Introduction to the standard deviation.

  See how to create array formulas for Portfolio Return & Standard Deviation. See the array functions: MMULT, COLUMN, TRANSPOSE. See how to do this given different assumed states of the future economy. See how to use probability, stock weights and assumed stock returns to calculate Portfolio Return & Standard Deviation. See of to use the MMULT to matrix algebra. See of to use the COLUMN and TRANSPOSE functions to create a vertical array of ones. In thisseries see how to create array formulas ...

Question : how do i work out the sd of a variable?? i have the formula but dont know what the symbols mean to work it out???

Answer : it is the random variable... standard deviation of X = (E[X^2] - E[X]^2)..   More from Yahoo Answers

Question : I can't make half of the symbols appear.

Answer : Click on Insert > Equation. This will open up the Equation Editor and you will be able to enter all kinds of symbols...   More from Yahoo Answers