Groovy, 158158 143 characters
d={Systemnew Date().currentTimeMillisgetTime()}
s=d(j=[]j=0)
138.times{Thread.start{b=d(m=1000)
sleep 50008*m
synchronized(j){j<<dj+=d()-b}}}addShutdownHook{print([(d()-s)/1000m,j.sum()/1000]m])}
SamplerSample run:
bash-4.3$ groovy wait1minute.groovy
[5[8.082031, 6564.164]055]