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?


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That's a bit more informative - thanks.

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

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

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.

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?

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.

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.

Originally Posted by neutral5

Why all of your comments are incredibly aggressive madam? Please calm down.

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.