# Can't correctly calculate amount of saved defects in 2019

1. ## Can't correctly calculate amount of saved defects in 2019

Hello

I can't solve this mathematics problem:

What I want: For producing these products, In 2018 X method was in use; in 2019 Y method in use. How many products I saved from being defect with the new method.

Probably, I put dumbly thought formulas at these cells: H3, H4, H9. Why I get 243 instead of 220? Which steps can give me 220?

Screenshot_1.jpg

2. ## Re: Mathematical logic problem

We would very much like to help you with your query, however the thread title does not really convey what your request is about.

Please take a moment to amend your thread title. Make sure that the title properly explains your request. Your title should be explicit and not be generic (this includes function names used without an indication of what you are trying to achieve).

Please see Forum Rule #1 about proper thread titles and adjust accordingly. To edit the thread title, open the original post to edit and then click on Go Advanced (bottom right) to access the area where you can edit your title.

(Note: this change is not optional. No help to be offered until this moderation request has been fulfilled.)

3. ## Re: Can't correctly calculate amount of saved defects in 2019

That's a bit more informative - thanks.

4. ## Re: Can't correctly calculate amount of saved defects in 2019

I think it's because D9 isn't a weighted average.

5. ## Re: Can't correctly calculate amount of saved defects in 2019

Originally Posted by AliGW
I think it's because D9 isn't a weighted average.
But why? D9 is not coming from average of D3 and D4

6. ## Re: Can't correctly calculate amount of saved defects in 2019

Basically, it boils down to this. The way you have formulated the problem, the sum of the saved defects is not the same as the saved defects of the sum. Proving this is a tedious algebra exercise/lesson, so I won't bother with it all (unless you really need me to). It's not difficult algebra, just tedious. If you need the practice, it might be useful to take the time to combine all those formulas into one to show yourself that they are not the same.

Other than that, I cannot suggest anything. If you want the saved defects of the sum to be the same as the sum of the saved defects, you are going to need to revamp how you are calculating saved defects so that it will work out that way. Since I do not know how you came to this definition for saved defect or what exactly you are trying to measure here, I cannot suggest anything.

7. ## Re: Can't correctly calculate amount of saved defects in 2019

Thanks Yes, I should have clearly defined what I want to measure. I'm updating my first message.

New message from the OP (moved by moderator):

I can't solve this mathematics problem:

What I want: For producing these products, In 2018 X method was in use; in 2019 Y method in use. How many products I saved from being defect with the new method.

Probably, I put dumbly thought formulas at these cells: H3, H4, H9. Why I get 243 instead of 220? Which steps can give me 220?

8. ## Re: Can't correctly calculate amount of saved defects in 2019

I really don't think you've stated the case any more clearly than you did before.

The maths just don't work, as Mr Shorty has pointed out. Have a look again at his last sentence: you have not addressed this, so we are no closer to knowing what exactly you are trying to show.

Explain in WORDS what the purpose is and what you think your calculations show.

9. ## Re: Can't correctly calculate amount of saved defects in 2019

Originally Posted by AliGW
NO!!!!

Do NOT post-edit posts.
It makes the thread impossible to follow. Instead, add a new explanation to a new post to this thread.
Actually, I don't agree with this. Because newcomers who will start to read my thread will not see "what I want", and will stop reading and digging further. But, it is ok if it is a solid forum rule.

I explained it already: "What I want: For producing these products, In 2018 X method was in use; in 2019 Y method in use. How many products I saved from being defect with the new method"...I don't know how can I make this explanation more clear

10. ## Re: Can't correctly calculate amount of saved defects in 2019

As MrShorty said, the math won't work. However, I believe if you compare based on the same quantities (pro-rated), then the math will work.
I've attached a file where it works for the numbers I enter.

11. ## Re: Can't correctly calculate amount of saved defects in 2019

Actually, I don't agree with this.
You are entitled to your opinion, but as a Moderator it's my job to ensure that the thread remains accessible to all participants, which is why I copied the new message to its correct chronological place in the thread. You are required to comply with moderation requests, whether or not you agree with them. That's just the way it is, I am afraid.

I explained it already:
You explained what you want, but you did not explain how you had arrived at the calculation you are using, or why you thought the results should be what your thought they should be. As I and Mr Shorty and now Gregb11 have all pointed out, your maths is just plain wrong.

12. ## Re: Can't correctly calculate amount of saved defects in 2019

Originally Posted by Gregb11
As MrShorty said, the math won't work. However, I believe if you compare based on the same quantities (pro-rated), then the math will work.
I've attached a file where it works for the numbers I enter.
Thank you I did a different move which is similar to yours. I adapted the 2018 data form to 2019 data while keeping its rate as the same. If the total input numbers are not the same, it creates an unbalanced comparison

13. ## Re: Can't correctly calculate amount of saved defects in 2019

Originally Posted by neutral5
Please don’t be rude. There is nothing aggressive in my comments. I am stating what the issue is and why it is proving difficult to help you.

##### Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts

Search Engine Friendly URLs by vBSEO 3.6.0 RC 1