I am new in the community and I d like to ask this. Let's assume that i have a sample which is a time series. I want to know if the difference in values has a statistical significant change. An example :
"Has the average BMI of men been increased the last 30 years?"
So i have the time series and i want to know the standard deviation( which i can easily calculate) BUT i want to know the significance of the SDEV.