How to translate summation notation problems in excel

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i = 1 n = 17 yi = 20 year series of data... e.g for the first year = 30222 2nd year = 316822


huhu someone help me please....thank you!!!!

See if the attached workbook does what you are looking for.
Here is a fragment of the file:

summation.png

You need to populate the blue shaded cells.
Formulas in B3:b6: are as shown in col-A
Copy B1:B6 rightwards as far as you need (as big an "n" as you need)

The final answer is in B9 which has the formula:

Formula:

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See the attached workbook:

Thank you but I was confused what do you mean populate huhu

disregard what I said with the years i'm sorry.

actually I have like 17 per say entity of of yi.. eg. A = 12618 B = 30222 and so on until Q(which is the 17th)
i = 1 and i = 17


however, looking back again on your formula.. I think it was right.. I just don't know what do you mean by populate...? huhu thank you.

By "populate" I mean that you need to enter values for y_i

y₁ according to your example is 30222 and goes in cell B2
y₂ according to your example is 316822 and goes in cell C2.

You need to enter the remaining values for y₃, y₄ . . . y₁₇

You also need to set n to 17 in cell B8.