- #1
Iwicka
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Homework Statement
Asked to find Weibull distribution parameters, [itex]\theta[/itex] and [itex]\tau[/itex], using Excel's Solver feature. I know that the 25th percentile is 1500 and the 75th percentile is 250000.
Homework Equations
Weibull CDF = 1-exp(-(x/[itex]\theta[/itex])^[itex]\tau[/itex])
The Attempt at a Solution
I have solved the solution by paper to yeild: [itex]\theta[/itex]=86384.36181, [itex]\tau[/itex]=0.307375855.
In Excel's Solver:
Objective cell is the formula: =EXP(-(1500/C2)^C3)-0.75
Optimize value of: 0
By Changing Cells: C2 and C3, which are my [itex]\theta[/itex] and [itex]\tau[/itex] values respectively.
Constraints: cell with formula: EXP(-(250000/C2)^C3)-0.25 constrained to be 0.
The solver is not able to find the solution. What am I doing wrong?