Which trendline?

[Liked]

So I have this figure in excel, and I want to add a trendline. Which one should one use? If I use a different trendline I get a slightly different conclusion from my data. What is the rule?
Thanks.

[Stoob]

So I have this figure in excel, and I want to add a trendline. Which one should one use? If I use a different trendline I get a slightly different conclusion from my data. What is the rule?
Thanks.

Lies... damn lies..... statistics!

Whatever one best suits you!

[Rob2020]

Lies... damn lies..... statistics!

Whatever one best suits you!

Great book, everyone should read it
How to lie with statistics

[Liked]

Lies... damn lies..... statistics!

Whatever one best suits you!

That's what I have been doing so far, but I want to check if the conclusions would be the same if I was objective

[East_coast]

Which ever one fits the best but not too obscure. You're surely just trying to mathematically model the relationship between a couple of variables.



If you click the 'show equation' button you can see the formula for the trend line. This can be very handy if you have data to analyse and 'predict' the outcome or you need to write some software to replicate non-linear relationship.

[Liked]

Original Post Deleted

No.

[Liked]

Which ever one fits the best but not too obscure. You're surely just trying to mathematically model the relationship between a couple of variables.



If you click the 'show equation' button you can see the formula for the trend line. This can be very handy if you have data to analyse and 'predict' the outcome or you need to write some software to replicate non-linear relationship.

Thanks. Yes, but surely there is a more "scientific" way to do it than just by looking which one seems to fit the best? Should I check the formula for each line, and then chose the one with the highest R2?

[East_coast]

Thanks. Yes, but surely there is a more "scientific" way to do it than just by looking which one seems to fit the best? Should I check the formula for each line, and then chose the one with the highest R2?

Why do you need the trendline?
Who is the customer?

[Liked]

Why do you need the trendline?
Who is the customer?

No customer. I am self employed
I just want to see the relationship between two things. Say unemployment and GDP. And see for example whether higher unemployment has a deleterious impact on the GDP, and up to what level of unemployment. Whether the relationship is linear, or whether it stops being linear when unemployment reaches (say) 10%, and then there is no relationship any longer. Something like this (but not exactly this).
Thanks.

[East_coast]

Choosing a trendline is not an exact science. The data you are looking at have probably gone through many filters and groupings.

https://support.office.com/en-za/art...0-d0c93161daa8

You should also look at the correlation number to give you a feel of how aligned the numbers are.

but remember correlation does not mean causation