<p>Mean and median identical with no variation in FASTQC results
After using FASTQC, in the section of &quot;Per Base Sequence Quality&quot; I encountered a problem when I saw the Box &amp; Whisker type plot. The median value and the mean quality are the same and I have no yellow box, as shown here:</p>
<p><a href="https://i.sstatic.net/g90gY.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/g90gY.jpg" alt="enter image description here" /></a></p>

CC BY-SA 4.0
2023-06-25T12:09:07.110Z
Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.
Community
CC BY-SA 4.0
2023-06-25T17:56:08.607Z
Can you show the first few records from your fastq file and say roughly how many reads you have? Where did the fastq come from? Is it possible that 'dummy' quality scores of Q30 were added by someone?
Chris_Rands
CC BY-SA 4.0
2023-06-28T15:02:03.540Z
Please look to comply with @Chris_Rands. I don't think anyone will answer until this request is fulfilled.
M__
<fastqc>
Mean and median identical with no variation in FASTQC results
# Mean and median identical with no variation in FASTQC results

(Asked by: username_0 on 2023-06-25)

Mean and median identical with no variation in FASTQC results
After using FASTQC, in the section of "Per Base Sequence Quality" I encountered a problem when I saw the Box & Whisker type plot. The median value and the mean quality are the same and I have no yellow box, as shown here:

[![enter image description here](https://i.sstatic.net/g90gY.jpg)](https://i.sstatic.net/g90gY.jpg)

**Tags:** fastqc
> **Comments:**
> **username_1**: Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.  
> **username_2**: Can you show the first few records from your fastq file and say roughly how many reads you have? Where did the fastq come from? Is it possible that 'dummy' quality scores of Q30 were added by someone?  
> **username_3**: Please look to comply with @Chris_Rands. I don't think anyone will answer until this request is fulfilled.  

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## 0 answers

