Hi Liz,

Let me backstep and make an additional point about the waver output being
greater than 1.

In theory, if one were to sample continuously, then even 2 stimuli, no matter
how far apart in time, would convolve with the scaled gamma variate function
to produce a maximum greater than 1.

But sampling every 2 seconds, it is common not to see where the convolution
results in a values greater than one, unless 2 stimuli are less than about 6
seconds apart. Try these waver commands:

waver -GAM -dt 1.0 -peak 1 -numout 15 -inline 1 0 0 0 0 0 1
waver -GAM -dt 2.0 -peak 1 -numout 15 -inline 1 0 0 1

These are 2 scaled GAM functions convolved with "on" points 6 seconds apart,
one sampled every second, the other every 2 seconds. In either case you see
the two peaks, but neither is greater than 1. Now put them 5 seconds apart:

waver -GAM -dt 1.0 -peak 1 -numout 15 -inline 1 0 0 0 0 1
waver -GAM -dt 2.5 -peak 1 -numout 15 -inline 1 0 1

Note that in this second pair, the dt was changed to 2.5 (since we need 5
seconds to be a multiple of our TR, say).

Here you see the two curves again, but the maximum sampled value is above
1.0 in each case (where the added curves overlap each other).

I hope that wasn't too much babble on the subject... :)

- rick