Answer: 1.645
Explanation:
Given : The mean annual income of certified welders is normally distributed with a mean of $50,000 and a population standard deviation of $2,000.
Alternative hypothesis : [tex]H_a:\mu\neq50000[/tex]
Since the alternative hypothesis is two-tailed , so the hypothesis test is a two-tailed test.
Also, Significance level : [tex]\alpha=0.10[/tex]
For two tailed test the to find the critical value , we need to find the z value or t-value for significance level of [tex]\alpha/2[/tex].
The critical value will be:
[tex]z_{0.10/2}=z_{0.05}=1.645[/tex]
