plus 2 times (the inverse logit of ((x minus c1.5) over sigma) minus the inverse logit of ((x minus c2.5) over sigma)) plus

plus three times the inverse logit of ((x minus c2.5) over sigma),

where inverse logit of x equals e to the x over (1 plus e to the x) is the logistic curve displayed in Figure 5.2a on page

Thanks for letting me play, even though my book is not as much fun as the others. (Though now that I did this, I notice there is an extra plus in the book, at the end of the first line entered above.)

_Data Analysis using regression and multilevel/hierarchical models_ gelman and hill

]]>Biliana, that is really funny! Go chocolate!

]]>“Problem 20. As an advertising campaign, a chocolate factory places golden tickets in some of its candy bars, with the promise that a golden ticket is worth a trip trough the chocolate factory, and all the chocolate you can eat for life. If the probability of finding a golden ticket is p, find the mean and the variance of the number of candy bars you need to eat to find a ticket.”

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