diff --git a/iis_project/plotting_utils.py b/iis_project/plotting_utils.py
index 6ca77a5..c00d264 100644
--- a/iis_project/plotting_utils.py
+++ b/iis_project/plotting_utils.py
@@ -1,4 +1,22 @@
-from math import ceil, log
+from math import ceil
+from typing import Optional
 
-def suggest_bins_num(n: int) -> int:
-    return max(int(ceil(log(n))), 10)
+from scipy.stats import norm
+
+SND_QUARTILE: float = 0.674490
+
+def suggest_iqr_to_range_to_suggest_bins_num(n: int) -> float:
+    p = 1 / (n + 1)
+    return (SND_QUARTILE / norm.ppf(1 - p/2))
+
+def suggest_bins_num(n: int, iqr_to_range: Optional[float] = None, scale: float = 1.) -> int:
+    if n <= 0:
+        raise ValueError(f'n should be >= 1, got {n}')
+    if (iqr_to_range is not None) and (iqr_to_range <= 0.):
+        raise ValueError(f'iqr_to_range should be > 0 or None, got {iqr_to_range}')
+    if scale <= 0.:
+        raise ValueError(f'scale should be > 0, got {scale}')
+    if iqr_to_range is None:
+        iqr_to_range = suggest_iqr_to_range_to_suggest_bins_num(n)
+    t = 0.5 * scale * (1. / iqr_to_range) * (n ** (1. / 3))
+    return int(ceil(t))