Respuesta :
Answer:
The large sample must be selected if the company wants to be 98% confident that the true mean differs from the sample mean by no more than 2 days
n = 62.5427≅63
Step-by-step explanation:
Step1:-
Given maximum of error = M.E = 2 days
Given population standard deviation σ = 6.8 days
98% confident level Z₀.₀₂ = 2.326
Step2:-
we know that the maximum of error
[tex]M.E = \frac{Z_{\alpha } S.D }{\sqrt{n} }[/tex]
cross multiplication , we get
[tex]\sqrt{n} = \frac{Z_{\alpha } S.D }{M.E }[/tex]
squaring on both sides, we get
[tex]n = (\frac{Z_{\alpha } S.D }{M.E })^2[/tex]
[tex]n = (\frac{2.326 X 6.8}{2} )^{2}[/tex]
on calculation , we get
n = 62.5427
Conclusion:-
The large sample must be selected if the company wants to be 98% confident that the true mean differs from the sample mean by no more than 2 days
n = 62.5427≅63
