diff --git a/presentation/spin_chain/bootstrap.py b/presentation/spin_chain/bootstrap.py
new file mode 100644
index 0000000..71ace1d
--- /dev/null
+++ b/presentation/spin_chain/bootstrap.py
@@ -0,0 +1,14 @@
+import numpy as np
+from collections import Counter, deque
+
+def bootstrap(m, nsample, resample_len, nresamples, f):
+    whole_sample = np.zeros(nsample)
+    whole_sample[m:] = 1
+
+    results = deque()
+    for _ in range(nresamples):
+        sample = np.random.choice(whole_sample, resample_len)
+        results.append(f(sample))
+
+    results = np.array(results).astype(np.double)
+    return np.std(results)