Changes

*If alpha=1, then the failure rate of the device is constant over time.  

*If alpha=1, then the failure rate of the device is constant over time.  

*If alpha>1, then the failure rate of the device increases over time.  

*If alpha>1, then the failure rate of the device increases over time.  

*The equation for cumulative distribution function is: <math>F(x,\alpha,\beta) = 1-e^-{(\frac{x}{β})}^α</math>

*The equation for cumulative distribution function is: <math>F(x,\alpha,\beta)</math> =<math>1-e^-{(\frac{x}{\beta})}^\alpha</math>.

*The equation for probability density function is:

*The equation for probability density function is:

<math>f(x,\alpha,\beta) = \frac{\alpha}{\beta^\alpha}.x^{\alpha-1}.e^-{(\frac{x}{\beta})}^\alpha.</math>

<math>f(x,\alpha,\beta) = \frac{\alpha}{\beta^\alpha}.x^{\alpha-1}.e^-{(\frac{x}{\beta})}^\alpha.</math>

     2. x is negative.

     2. x is negative.

     3. alpha<math>\le 0</math> or beta <math>\le 0</math>

     3. alpha<math>\le 0</math> or beta <math>\le 0</math>

 

==Examples==

==Examples==

#=WEIBULL(202,60,81,TRUE) = 1

#=WEIBULL(202,60,81,TRUE) = 1