Question

Noise levels at 5 volcanoes were measured in decibels yielding the following data: 126,155,175,163,162 Construct the 98% confidence interval for the mean noise level at such locations. Assume the population is approximately normal. Step 3 of 4 : Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places. Step 4 of 4: construct the 98% confidence interval.

Answer 1

sample mean         x=	156.200
sample size             n=	5
sample std deviation s=	18.349
std error sx=s/√n=	8.2061

for 98% CI; and 4 df, critical t=	3.7470
margin of error E=t*std error                            =	30.7482
lower bound=sample mean-E =	125.4518
Upper bound=sample mean+E=	186.9482
from above 98% confidence interval for population mean =(125.45,186.95)

Step 3 of 4 :

critical value =3.747

Step 4 of 4:

98% confidence interval =(125.452 , 186.948)