The Horner rainfall intensity formula for Type I extreme value distribution with a

$50-$year return period at stations A and B is as below, as determined by the Thiessen

polygon method, yields station weights of $40\%$ for station A and $60\%$ for station

B$.$

Station A : I $=\frac{1051\mathrm{.}341}{(t+9\mathrm{.}158{)}^{0\mathrm{.}519}}$

Station B : I $=\frac{1217\mathrm{.}747}{(t+13\mathrm{.}528{)}^{0\mathrm{.}513}}$

Please design the rainfall hyetograph $($centered type$)$ for a one$-$hour rainfall

duration with a $50-$year return period, and indicate the percentage of rainfall at

each hour.

Notice: Please show your calculate step and fallow the format as below.

Hint: Use Excel is much easier to do this!

i need details about the formulas used in excel