229k views
1 vote
HELPPP PLEASEEE! I tried everything from adding to dividing, subtracting, multiplying but still no correct answer. Can someone help me out here please? I am not sure where to start either now. Thank you for your time.

HELPPP PLEASEEE! I tried everything from adding to dividing, subtracting, multiplying-example-1
User Nidhin S G
by
8.7k points

1 Answer

6 votes

You have some data points labeled by
x. They form the set {3, 5, 7}.

The mean,
\bar x, is the average of these values:


\bar x = \frac{3+5+7}3 = \frac{15}3 = 5

Then in the column labeled
x-\bar x, what you're doing is computing the difference between each data point
x and the mean
\bar x:


x=3 \implies x-\bar x = 3 - 5 = -2


x=5 \implies x-\bar x = 5-5 = 0


x=7 \implies x-\bar x = 7 - 5 = 2

These are sometimes called "residuals".

In the next column, you square these values:


x=3 \implies (x-\bar x)^2 = (-2)^2 = 4


x=5 \implies (x-\bar x)^2 = 0^2 = 0


x=7 \implies (x-\bar x)^2 = 2^2 = 4

and the variance of the data is the sum of these so-called "squared residuals".

User Henning Dodenhof
by
8.1k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories