Update README.md

README.md

@@ -15,4 +15,10 @@ https://www.kaggle.com/code/reginliu/perplexity
 | [causallm_14b.IQ2_XXS.gguf](https://huggingface.co/Limour/CausalLM-14B-GGUF/blob/main/causallm_14b.IQ2_XXS.gguf) | 4.98 | 15.0160 +/- 0.15004 | 152064 | 15.0160 |
 | [Yi-9B-200K_iQ3xxs.gguf](https://huggingface.co/MarsupialAI/Yi-9B-200K_iMatrix_GGUF/blob/main/Yi-9B-200K_iQ3xxs.gguf) | 3.47 | 6.8157 +/- 0.05453 | 64000 | 16.1941 |
 | [Fi-9B-200K-Q8_0.gguf](https://huggingface.co/DisOOM/Fi-9B-GGUF/blob/main/Fi-9B-Q8_0.gguf) | 9.38 | 6.8402 +/- 0.05741 | 64000 | 16.2523 |
-| [causallm_7b.Q5_K_M.gguf](https://huggingface.co/TheBloke/CausalLM-7B-GGUF/blob/main/causallm_7b.Q5_K_M.gguf) | 5.53 | 16.5278 +/- 0.18005 | 152064 | 16.5278 |
+| [causallm_7b.Q5_K_M.gguf](https://huggingface.co/TheBloke/CausalLM-7B-GGUF/blob/main/causallm_7b.Q5_K_M.gguf) | 5.53 | 16.5278 +/- 0.18005 | 152064 | 16.5278 |
+| [Qwen1.5-22B-Chat-Merge-Q4_0.gguf](https://huggingface.co/DisOOM/Qwen1.5-22B-Chat-Merge-GGUF/blob/main/Qwen1.5-22B-Chat-Merge-Q4_0.gguf) | 12.6 | 21.9669 +/- 0.28980 | 152064 | 21.9669 |
+
+For a model that returns tokens completely at random, we have
+$$ P(token|context) = \frac{1}{n_{vocab}}, \quad PPL = \sqrt[N]{\left(\frac{1}{P}\right)^N} = n_{vocab} $$
+therefore
+$$ PPL_{adjust} = \frac{PPL}{n_{vocab}}  \times 152064  $$