Question

Noise levels at 3 volcanoes were measured in decibels yielding the following data: 142,113,135 Construct the 90% 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

Answer 1

From the given data, the following statistics are calculated:

n = 3

= 130

s = 15.1327

SE = s/

= 15.1327/ = 8.7369

= 0.10

ndf = n - 1 = 3 - 1 = 2

From Table, critical values of t = 2.9200

Confidence interval:

130 (2.92 X 8.7369)

= 130 25.5517

= ( 104.488 ,155.552)

Confidence interval:

104.488 < < 155.552

Answer to question asked:

Critical value = 2.920