On Friday 31 October 2003 20:40, Marc Belisle wrote: > Howdee, > > One of my student spotted something I can't explain: a probability > >1 vs a normal probability density function. > > > dnorm(x=1, mean=1, sd=0.4) > > [1] 0.9973557 > > > dnorm(x=1, mean=1, sd=0.39) > > [1] 1.022929 > > > dnorm(x=1, mean=1, sd=0.3) > > [1] 1.329808 > > > dnorm(x=1, mean=1, sd=0.1) > > [1] 3.989423 > > > dnorm(x=1, mean=1, sd=0.01) > > [1] 39.89423 > > > dnorm(x=1, mean=1, sd=0.001) > > [1] 398.9423 > > Is there a bug with the algorithm?
The *area* under the density curve corresponds to the probability in the corresponding interval...as you might have learned in a statistics course. So it's perfeclty alright for a density function to exceed 1 if the area under the whole curve still equals one. Immediately obvious for curve(dunif(x, min = 0, max = 0.5)) hth, Z > Thanks, > > Marc > > ======================== > Marc B�lisle > Professeur adjoint > D�partement de biologie > Universit� de Sherbrooke > 2500 boul. de l'Universit� > Sherbrooke, Qu�bec > J1K 2R1 CANADA > > T�l: +1-819-821-8000 poste 1313 > Fax: +1-819-821-8049 > Courri�l: [EMAIL PROTECTED] > Site Web: > www.usherbrooke.ca/biologie/recherche/ecologie/Belisle/belisle.html > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
