Variance and standard deviation

Question 1

What is the formula for variance ?

Answer 1

summation of x squared /n - (summation of x/n)squared

Question 2

What is the formula for variance in a frequency table ?

Answer 2

summation of fx /f - (summation of fx/f) squared

Question 3

What is variance also known as ?

Answer 3

the mean of the squares - the square root of the mean

Question 4

What is the standard deviation ?

Answer 4

the square root of the variance

Question 5

What do you use when you have a table ?

Answer 5

the midpoint of each class