diff --git a/engine/engine.py b/engine/engine.py
index e304aeb..cacac7a 100644
--- a/engine/engine.py
+++ b/engine/engine.py
@@ -21,7 +21,7 @@ class MarketEngine():
     def act(self, prices):
         demand = generate_demand(prices, *self.demand)
         sample_n = lambda n, human: [sample_behavior(demand, human=human) for _ in range(n)]
-        human_t, agent_t = sample_n(100, True), sample_n(100, False)
+        human_t, agent_t = sample_n(self.Nhumans, True), sample_n(self.Nagents, False)
         trajectories = human_t + agent_t
         demand_estimate = estimate_demand(trajectories)
         return demand_estimate
diff --git a/engine/studies/full_factorial.py b/engine/studies/full_factorial.py
index 9b4d1eb..92210b2 100644
--- a/engine/studies/full_factorial.py
+++ b/engine/studies/full_factorial.py
@@ -56,7 +56,7 @@ def run_single(cfg: dict) -> dict:
         "id": cfg["id"],
         "config": cfg,
         "total_reward": total_reward,
-        "avg_reward": total_reward / steps,
+        "avg_reward": total_reward / steps if steps > 0 else 0.0,
         "steps": steps,
     }