Variance and standard deviation Flashcards
unit 2.4
1
Q
What is the formula for variance ?
A
summation of x squared /n - (summation of x/n)squared
2
Q
What is the formula for variance in a frequency table ?
A
summation of fx /f - (summation of fx/f) squared
3
Q
What is variance also known as ?
A
the mean of the squares - the square root of the mean
4
Q
What is the standard deviation ?
A
the square root of the variance
5
Q
What do you use when you have a table ?
A
the midpoint of each class
