Answer: 1.282
Step-by-step explanation:
Given : Significance level : [tex]\alpha= 10\%=0.10[/tex]
The alternative hypothesis : [tex]H_a:\mu<\mu_0[/tex], which is left tail-ed , it means the test is left -tailed test i.e. one -tailed test.
By using the standard normal distribution table , we have
The critical value for a one-mean z-test corresponding to the significance level 0.10 is 1.2815515 or approximately 1.282
Hence, the critical value or values for a one-mean z-test at the 10% significance level if the hypothesis test is left-tailed = 1.282
