How to calculate MOS_zscore in koniq10k datasets? about hyperiqa

[SSL92]

In our downloaded score file, there's one column 'MOS_zscore' attached behind column SD, maybe you could refer to the published dataset to see if there's any update.

[wangbin2018]

Yes, MOS_zscore = 77.38362, but I don not know how to calculate this Mark.
Another datasets maybe only give MOS mark，So I want to understand.
Thank for your replay！

[SSL92]

This might be the post-processed MOS score, you can refer to their origin paper for an answer.

[wangbin2018]

I read this paper already，but only got how to calculate MOS，not MOS_zscore.
Maybe I didn't see it O.O

[ilovetlic]

image_name: the image file name
c1-c5: number of ratings for each ACR value
c_total: total number of judgments per image
MOS: Mean Opinion Scores of the 5-point ACR
​SD: ​Standard Deviation of the MOS
MOS_zscore: ACR scores are first normalised for each user by z-scoring the user ratings