Dixon Q Test for Outliers 

because the question stated there that 'use 5% significant level' which also means that the alpha is 0.05 (conversion of percent to decimal places)

It doesn't matter

+Minhua Zhu that was asked as a questoon is the test statistic greater than critical value (is 0.333 greater than 0.466) ..no. in that case "fail to reject" if we got a Test Stat of say 5 - then we would reject

What's important is the gap. When the outlier is bigger than all of the value, you may subtract the suspected outlier from the nearest value.