Answer:
•Lower confidence limit = $155.2109
•Upper confidence limit ,= $174.5891
Step-by-step explanation:
We are given:
U = 17
x' = $165.40
S.d = $21.70
a = 10℅ (90℅ confidence interval)
For s.d(x'), we have:
S/√u =
= 5.2630
Therefore, S.E (x') = $5.2630
At a= 0.10 (90℅ confidence level)
and degree of freedom = 16 (17-1)
90℅ confidence interval all around sample mean, will be:
(x' ± ; a S.E (x')
= (165.4±(174.6)(5.2630)
(165.5±9.189)
($156.2109, $175.5891)