Answer:
Upper confidence level (UCL) = 29367.875
Lower confidence level (LCL) =23061.064
Explanation:
Given : sample mean=26214.47
sample standard deviation=5969.25
sample size=15
degree of freedom=14
t critical value for 94% confidence with 14 degree of freedom=2.046
To Find : Upper confidence level (UCL) =?Lower confidence level (LCL) =?
Solution:
Formula for confidence interval =
![\left( \bar{X} \pm t_{(\alpha)/(2)} * (s)/(√(n)) \right)](https://img.qammunity.org/2020/formulas/mathematics/college/3liwev88z40xdpyx5x0uwktyfv8w9hsizl.png)
sample mean=
=26214.47
sample standard deviation = s =5969.25
sample size = n =15
t critical value for 94% confidence with 14 degree of freedom
=2.046
Substitute the values in the formula :
confidence interval =
![26214.47 \pm 2.046 * (5969.25)/(√(15))](https://img.qammunity.org/2020/formulas/mathematics/college/tqhtq0m8xy7qp9kendfxuw58pa9752plhb.png)
confidence interval =
to
![26214.47 + 2.046 * (5969.25)/(√(15))](https://img.qammunity.org/2020/formulas/mathematics/college/a5f1x7g8joq8cbaf3o4a3ihx57t410hsow.png)
confidence interval =
to
![29367.875](https://img.qammunity.org/2020/formulas/mathematics/college/afnzj5dmoktv1b7v8kca9xa955d9r6fqud.png)
Hence Upper confidence level (UCL) = 29367.875 and Lower confidence level (LCL) =23061.064