I am almost finished, I am just confused with one aspect. I am supposed to calculate the onset and decay, however the instructions are very vague.

Calculating Onset Time and Decay Time

Now you have all the information you need to calculate the onset time and decay time for each solar cycle. With what you've learned about spreadsheets so far, you should be able to do this on your own.

In addition, you should have Excel calculate the difference between the onset time and decay time for each solar cycle.

Finally, for all three values (onset time, decay time and difference), calculate the average and standard deviation for all 22 solar cycles.

Is there a difference?

Do I subtract the monthly maximum and minimum sunspot numbers, or am I subtracting the years where the maximums and minimums are occurring?

Quick help would be much appreciated. Unfortunately my project is due tomorrow.

I have everything else finished, except for this.

Thank you in advance for the help.