Job estimating

I've got some data that I want to find the best fit for.
Basically trying to create a tool to estimate future job time.
For this particular situation we've broken it into two tasks, small jobs, and large jobs. Roughly taking 1.5h and 2 hours each
As we add more and more past jobs to the excel sheet I want to be able to get more and more accurate estimating numbers

Job	Small items	Large items	Hours to complete
Job 1	0	50	112
Job 2	117	123	370
Job 3	492	352	1120

Formula:

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As we get more inputs I'd like to keep adding to the data and find a more and more accurate value for y and x.

I've added the analysis add on to excel and there is so much try I was hoping someone could point me in the right direction.(If the analysis tool is what the right direction is).

Hope the goal and situation make sense.

Thanks

Jonathan

How much of this is a statistics question (what is an appropriate analysis independent of programming language?) or is it more specific to Excel (I want to use a specific analysis technique in Excel)?

If the question is one of choosing an appropriate analysis, I'm not sure if we have anyone with enough expertise in statistics and/or knowledgeable enough about your specific needs to choose an analysis for you. If I had to guess, it almost looks like you want multi-variable regression which can be implemented using the data analysis tools or using the LINEST() function (https://support.microsoft.com/en-us/...rs=en-us&ad=us ). 3 data points, though, is a rather paltry data set for evaluating the appropriateness of multi-variable regression to the analysis.

If you help us understand the kind of analysis you want, we should be able to help you program that analysis into the spreadsheet.

Here is a link to a video about the LINEST function produced by an instructor at Highline College that may also be helpful: https://www.youtube.com/watch?v=ECA2VSOhbuU&t=22s
The LINEST function yielded the following values:
For the slope of the large items: 15.46391753
For the slope of the small items: -7.443298969
For the intercept: -661.1958763
As shown in the attached file these values can be checked using the original small, large to yield the original hours complete.
Let us know if you have any questions.

You're Welcome and thank you for the feedback. Please take a moment to mark the thread as 'Solved' using the thread tools menu above your first post. I hope that you have a blessed day.