In: Statistics and Probability
Calculate the lower confidence limit (LCL) of the mean for the following: x¯= 600, n = 94, σ = 8 (sigma), α = 0.10 (alpha).
Solution :
Given that,
= 600
= 8.8
n = 94
A ) At 95% confidence level the z is ,
=
0.10
/ 2 = 0.10 / 2 = 0.05
Z/2
= Z0.05 = 1.645
Margin of error = E = Z/2*
(
/n)
= 1.645 * (8 /
94 )
= 1.36
At 80% confidence interval estimate of the population mean is,
- E <
<
+ E
600 - 1.36 <
< 600 + 1.36
598.64 <
< 601.36
The lower confidence limit = 598.64