Percentile Function in Summarize Tool Not Working Correctly

[Qiu]

I test the  10% percentile for {1,2,3,4,5,6,7,8,9}, whch alteryx gives 1.8, while it should be 1.
According the help, it should return the value of the target row, which shall not result any decimal in this case.

[SeanAdams]

You are right @Qiu - it seems to be a continuous percentile rather than a discrete percentile.

[Qiu]

@SeanAdams 
I think you point out the cause. Thanks!