Answer :
Answer:
Upper confidence level (UCL) = 29367.875
Lower confidence level (LCL) =23061.064
Step-by-step 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 = [tex]\left( \bar{X} \pm t_{\frac{\alpha}{2}} \times \frac{s}{\sqrt{n}} \right)[/tex]
sample mean= [tex]\bar{x}[/tex] =26214.47
sample standard deviation = s =5969.25
sample size = n =15
t critical value for 94% confidence with 14 degree of freedom [tex]t_{\frac{\alpha}{2}}[/tex]=2.046
Substitute the values in the formula :
confidence interval = [tex]26214.47 \pm 2.046 \times \frac{5969.25}{\sqrt{15}}[/tex]
confidence interval = [tex]26214.47 - 2.046 \times \frac{5969.25}{\sqrt{15}}[/tex] to [tex]26214.47 + 2.046 \times \frac{5969.25}{\sqrt{15}}[/tex]
confidence interval = [tex]23061.064[/tex] to [tex]29367.875[/tex]
Hence Upper confidence level (UCL) = 29367.875 and Lower confidence level (LCL) =23061.064