SOLUTION: I need help. my teacher never touched this section. 2.2 Find the mean and the standard deviation of the set of numbers 5, 8,8,9,14,18,100.

Algebra ->  Statistics  -> Describing-distributions-with-numbers -> SOLUTION: I need help. my teacher never touched this section. 2.2 Find the mean and the standard deviation of the set of numbers 5, 8,8,9,14,18,100.      Log On


   

Question 1115412: I need help. my teacher never touched this section.
2.2 Find the mean and the standard deviation of the set of numbers 5, 8,8,9,14,18,100.
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
mean of
5, 8, 8, 9, 14, 18, 100 is:
%285%2B8%2B8%2B9%2B14%2B18%2B100%29%2F7=162%2F7 ≈ 23.143

and standard deviation is:
The standard deviation of a probability distribution is defined as the square root of the variance.
To find the variance, subtract the mean from each of the x values,
5-23.143+=+-18.143
8-23.143=+-15.143
8-23.143+=+-15.143
9-23.143+=+-14.143
18-23.143 = -5.143
100-23.143=76.857
Now square all the answers you have got from subtraction.
%28-18.143%29%5E2+=329.168449
%28-15.143%29%5E2+=229.310449
%28-15.143%29%5E2+=229.310449
%28-14.143%29%5E2+=+200.024449
%28-5.143%29%5E2+=+26.450449
%2876.857%29%5E2+=+5906.998449

Add all the Squared numbers,

Divide the sum of squares by %28n-1%29+ to get variance
variance=6946.262694%2F%28n-1%29 .... and in your case n=7
variance=6946.262694%2F6
variance=1157.710449
Find the square root of variance=standard deviation,
sqrt%281157.710449%29=34.02514436%29≈ 34.03