Video 2c, Relationship Exponential and Poisson distributions

[trabala38]

Hello David,

In the video for Quantitive Analysis 2.c, I think there is a mistake on slide 31.

For H=1hour and lambda=0.25 (like stated in the example), I get the following values:
=> P (Y > H) = Exp(-0.25*1) = 77.9% (instead of 60.7% stated on the slide)
=> P (Y < H) = 1- Exp(-0.25*1) = 22.1% (instead of 39.3% stated on the slide)

For H=12hours and lambda=0.25 (like stated in the example), I get the following values:
=> P (Y > H) = Exp(-0.25*12) = 5.0% (instead of 22.3% stated on the slide)
=> P (Y < H) = 1- Exp(-0.25*12) = 95.0% (instead of 77.7% stated on the slide)

Regards,

Trabala38

 

[David Harper CFA FRM]

Hi trabala38,

Yes, you are absolutely correct (my spreadsheet confirms and agrees with your numbers, but the results were not transferred). I apologize for the error, but thank you for your attention to detail.

Errata entry added here @ http://forum.bionicturtle.com/viewthread/5109/

I corrected the PowerPoint (PDF) presentation and uploaded the correction (the video remains mistaken of course).

Thanks, David