Statistics Question! Please help, thanks

Question

1. How would you determine the mean and standard deviation of a question? What are the formulas used?

Say if you were given a chart with 3 columns, 2 of them are blank, 1st one representing x the following data (numbers) which also has a ∑ = at the end of it, as well as the 3rd column.

What would I have to do in this scenario?

Answer 1

Mean = x‾ = sum of numbers / number of numbers

standard deviation = √∑( x - x‾ )² / n-1

example :

82 , 93 , 98 , 89 , 89

Mean = x‾ = 82+ 93 + 98 + 89 + 89 / 5

x‾‾ = 90

standard deviation = S = √ ∑( 82 -90) ²+ ( 93 - 90 )²+ ( 98-90)²+(89-90)²+(89-90)²/ 5-1

= S= √∑64+9+64+1+1/4

=S= √139/4 = 5·89

in you chart you have x , find mean and then with the help of mean find standard deviation.