Production managers, on an assembly line, must monitor the output to check if the level of defective products is greater than an average of 5 per production run. They continuously inspect a random sample of production runs and find the average number of defective parts produced. If they find a significant increase in the mean number of defective parts, they will stop the assembly line and fix the machinery. The hypotheses are:

Ho: = 5

Ha: > 5

Say a random sample of 25 production runs is taken, where the mean number of defective parts is found to be 4.3 parts with a standard deviation of 0.5 parts. If testing at the 1% level of significance, what is the critical value? Please give your answer correctly rounded to two decimal place.