The data given table $($Homework folder in Black Board$)$ are measured average annual rainfall

data for a gage station located in Edwardsville, IL and other $10$ gage stations around the City of

Edwardsville. This gage station was temporary located in another City $($Alton$,$ IL$)$ from $2004$ to

$2011$ and relocated in Edwardsville, IL again since $2012.$ Use double$-$mass curve to correct

$($adjust$)$ the inconsistence data at the Edwardsville, IL gage station from $2004$ to $2011.$

a$.$ Plot the slope of cumulative data using the measured values in the gage of interest and

reference gage stations $($total $10).$ b$.$ What is a combined slope of curve after adjusting the data?

Please, use Excel to solve this question, but do not have to turn in the excel sheet but the

plotted curve and slope value only.