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 ---
 
+### ASCII code
+
+Quality score is encoded as [ASCII characters](https://www.ascii-code.com/characters)
+Formula to find the probability of error
+P = 10 -Q/10
+[ASCII_base 33](https://drive5.com/usearch/manual/quality_score.html) is now almost universally used.
+ASCII 33 is the first “normal” ASCII character.
+
+---
+
 ## PacBio HiFi *vs* CLR
 
 ![Comparison between PacBio HiFi and CLR sequencing methods](../../images/quality-control/pacbio_hifi_vs_clr.png)