Answer: (A) 2.19
Step-by-step explanation:
As per given , we have
Sample size : n= 30
Average number of vacation days a U.S. worker takes per year : [tex]\overline{x}=16[/tex]
Sample standard deviation : s= 12
Significance level : [tex]\alpha= 1-0.99=0.01[/tex]
Degree of freedom : df= 29 (n-1)
The standard error(SE) of sample mean[tex](\overline{x})[/tex] is given by :-
[tex]SE=\dfrac{s}{\sqrt{n}}\\\\=\dfrac{12}{\sqrt{30}}=2.19089023002\approx2.19[/tex]
Hence, the standard error(SE) of sample mean[tex](\overline{x})[/tex] is 2.19.