[EMAIL PROTECTED] (J. Williams) wrote in message news:<[EMAIL PROTECTED]>... > On 3 Apr 2002 08:36:47 -0800, [EMAIL PROTECTED] (david) wrote: > > >u=2.7 minutes > >sigma=.6 minutes > > > >my main question is how do I get the Z value here? > > > >The question is something like this what is probability that the total > >check out time for next customers is less than 90 minutes? > > > >- I understand that Xi is (i=1,2,3) and > > W = X1 + X2 . . . . and > > P(W<90) = P(X bar<3) > > > >BUT > > > >How does (X bar<3) = P(Z<2.74) > > > >So my main question is how does (X bar<3)=P(Z<2.74)? > > > >Could someone please explain how does this work? > > > >Thanks in advance! > > check out this site: > http://psych-www.colorado.edu/~mcclella/java/normal/normz.html > It should give you a hint on how to obtain Z scores from a normal > distribution of scores. Are you sure about the above data? A mu of > 2.7 and a standard deviation of .6 with a -90 score seems a tad off > kilter to me. Maybe, I'm missing something here.
a tad off kilter indeed. what's missing!!! doesn't n have to be 30, not 3? smells like at homework assignment from here - concepts: standard error of the mean; z score equivalent for a given Xbar. go for it!!! . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
