Hi John,

Expanding on Neil's answer:

For equally spaced points

delta = Pi/50;
data = Table[N@Sin[x], {x, 0, Pi, delta}];
Total[delta*data]
(* 1.99934 *)

For unequally spaced points you can use Interpolation

xVals = Table[x + RandomReal[{-delta, delta}/2], {x, 0, Pi, delta}];
yVals = Sin[xVals];
points = Transpose[{xVals, yVals}];

iFun = Interpolation[points]
Integrate[iFun[x], {x, Min@xVals, Max@xVals}]
(* 1.9995 *)

John,

If the values are equally spaced use Total[] to integrate the curve and multiply by the time spacing. If not, you can do the calculation point by point

Regards

Neil