How to Calculate Standard D

Kevin Neufeld

Board Regular
Joined
Oct 6, 2014
Messages
50
I have a sample table below. It represents model sizes of products, that are measured in Feet. the sales quantity is the number of each model sized sold. I am wanting to know the Avg Size sold. So I used a weighted average. I also wanted to know the standard deviation of size sold. I have shown below in green, blue and red the end results of the 3 metrics I wanted. Below each I have the steps / formulas used to obtain each. Just wanted to confirm with this group I did this correct.

Thanks in Advance.

Model Size (Feet)Sales Quantity
121
1515
1840
21139
24237
27179
30569
33119
361057
394
42764
481073
5498
60261
660
7265
7514
7852
9045
10582
1356
1560
Total4820
Formula used for Total=SUM(B2:B23)
Avg Size
(wgt'd)
41.8
Formula used for - Avg Size
(wgt'd)
=SUMPRODUCT($A$2:$A$23,B2:B23)/SUM(B2:B23)
Standard Deviation15.1
Steps used for Standard Deviation
Step 1=B2*A2+A3*B3+A4*B4+A5*B5+A6*B6+A7*B7+A8*B8+A9*B9+A10*B10+A11*B11+A12*B12+A13*B13+A14*B14+A15*B15+A16*B16+A17*B17+A18*B18+A19*B19+A20*B20+A21*B21+A22*B22+A23*B23
Step 2=(B2*A2)*A2+(B3*A3)*A3+(B4*A4)*A4+(B5*A5)*A5+(B6*A6)*A6+(B7*A7)*A7+(B8*A8)*A8+(B9*A9)*A9+(B10*A10)*A10+(B11*A11)*A11+(B12*A12)*A12+(B13*A13)*A13+(B14*A14)*A14+(B15*A15)*A15+(B16*A16)*A16+(B17*A17)*A17+(B18*A18)*A18+(B19*A19)*A19
Step 3=B30/B25
Step 4=((B25*B31)-(B30^2))/((B25*(B25-1)))
Step 5=SQRT(B33)
 

Excel Facts

What is the last column in Excel?
Excel columns run from A to Z, AA to AZ, AAA to XFD. The last column is XFD.
Hello,

I did not check your formulas but I think that your results are correct.
I calculated:
Weighted Average: 41.7846473
Weighted STDEV: 15.12314028
Weighted Variance: 228.709372

Regards,
Bernd
 
Upvote 0

Forum statistics

Threads
1,203,071
Messages
6,053,375
Members
444,658
Latest member
lhollingsworth

We've detected that you are using an adblocker.

We have a great community of people providing Excel help here, but the hosting costs are enormous. You can help keep this site running by allowing ads on MrExcel.com.
Allow Ads at MrExcel

Which adblocker are you using?

Disable AdBlock

Follow these easy steps to disable AdBlock

1)Click on the icon in the browser’s toolbar.
2)Click on the icon in the browser’s toolbar.
2)Click on the "Pause on this site" option.
Go back

Disable AdBlock Plus

Follow these easy steps to disable AdBlock Plus

1)Click on the icon in the browser’s toolbar.
2)Click on the toggle to disable it for "mrexcel.com".
Go back

Disable uBlock Origin

Follow these easy steps to disable uBlock Origin

1)Click on the icon in the browser’s toolbar.
2)Click on the "Power" button.
3)Click on the "Refresh" button.
Go back

Disable uBlock

Follow these easy steps to disable uBlock

1)Click on the icon in the browser’s toolbar.
2)Click on the "Power" button.
3)Click on the "Refresh" button.
Go back
Back
Top