Calculating a number based on two percentages

**bluesbro** · 04-05-2012, 02:36 AM

Background:

I'm trying to figure out a way to calculate a number of occurences it would take to increase a percentage from X percent to X percent.

So - assume

52% is the current number. I want to reach 62% goal. How many single occurences would it take to increase.

The 52% percent number is a revolving door, meaning that it can constantly change based on the criteria.

So - assume I have 64 sample and 31 are rejected for a 52% effective rate. But everyday I produce another 10 samples. Those 10 samples can be either rejected or passed increasing or decreasing the % effective rate, in turn changing the total amount needed to reach the 62% goal.

Is this possible?

**dilipandey** · 04-05-2012, 02:41 AM

Hi bluesbro,

Welcome to the forum.

Would suggest you to look into " goal seek" feature of Excel. ... post a sample file in case of any issues. thanks.

Regards,
DILIPandey

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**bluesbro** · 04-05-2012, 03:03 AM

That doesn't quite work for what I need. Since the samples will keep changing I want the end result to continue to change as well. The samples will continue to be pasted in the worksheet and changed from day to day.

**bonny24tycoon** · 04-05-2012, 05:32 AM

Looking at your figures and as per calculation it would take 81.6 samples to achieve your 62.0%.

I have just made that the Unique figure to calculate the "Sample needed to attain goal". Try changing the 81.60 in your sample1 field and you should see the change..

Let me know if this resolves your query.

Attachment 148922

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**bluesbro** · 04-16-2012, 09:04 PM

Sorry bonny that doesn't work for me either. I know I can change the sample, in fact the sample will change frequently. I want the total number or sample (addiitonal sampled needed to auto-cacluate based on the percentages of actual and goal.